What is the logic for the map maker classifying the map this way, specifically in Canada?

The main purpose is – per caption – to illustrate the varying degrees of censorship:

1. Dictatorial Control of the Agencies of Public Communication
2. Varying Degrees of Control, Censorship and Intimidation
3. Relative Freedom from Official Supervision

For Quebec, no definitive solution seems to be known. But there are convincing hypotheses out there:

The situation in Quebec in 1938

An element that will not fail to challenge the Quebec reader is the status of Quebec in this grid of analysis of freedom of expression in the world: neither in black like Nazi Germany, nor in yellow as the United States where freedom of expression is protected by the First Amendment to the Constitution, but in gray, in the company of the Canadian province of Alberta, colonies of French and British empires, Baltic nations and several Latin American countries .

But why is Quebec colored in gray? For US observers Cotton and Ackerman, why is Quebec threatened by the "new Black Death"? The map remains silent on this subject: we put forward three hypotheses.

First hypothesis: the domination of the clergy

The domination of religious powers in Quebec could be a potential target. During the 1930s and 1940s, the Catholic Church opposed the government's desire to promote economic liberalism while supporting the struggle against communism and all forms of socialism. For the citizens of Quebec, the strong influence of the clergy is reflected in social pressure contrary to the principle of freedom of conscience and expression. In support of this hypothesis, let us recall the boycott orchestrated by the Catholic Church against Ken Magazine : it illustrates well the marked opposition between the clerical ideology of the time and the progressive factions of the society.

Second hypothesis: nationalist aspirations

The economic crisis of the 1930s brought many economic and social upheavals. At this point in history, for its neighbors to the south, does Quebec embody a sort of "gray zone" because of its cultural differences and its autonomist ambitions, which may pose a threat to Anglo-American hegemony. American on the continent? In the context of the rise of fascist ideologies on the Old Continent, was the assertion of French-Canadian nationalism causing concern?

Third hypothesis: the Unionist Government

Does the map designed by Cotton seek to denounce the political regime imposed by the National Union of Maurice Duplessis ?

The Union Nationale cabinet, 1947-1948: the defender of the rights of the province and his team of patriots, wall calendar, Quebec, National Union, 1947.
This calendar highlights the cabinet of the National Union formed by Maurice Duplessis during his second term. Shortly after its publication, the provincial elections of July 28, 1948 will create a real Unionist tidal wave thanks to the party's well-equipped coffers and modern marketing strategies. The main electoral slogan is striking: "Liberals give to strangers; Duplessis gives to his province.

In 1938, however, Maurice Duplessis is a new party leader who does not yet have the influence, power and arrogance that will be his trademark from 1944. The populist style of Duplessis can recall up to a certain point that of a Mussolini, but the period known as the Great Darkness in Quebec covers after all only the fifteen years after the war.

US activists defending freedom of expression may have noted the passage in 1937 of the Protecting the Province from Communist Propaganda Act (better known as the "Padlock Act"). Any place for the propagation of Communism or Bolshevism could now be condemned by the Attorney General. This legal measure could be a threat to trade union or religious organizations. In particular, it served to legitimize the closing of newspapers such as the communist weekly Clarté (which occurred on November 9, 1937) and numerous searches.

–– Appel à tous : la liberté d’expression au Québec en question en 1938 Publié le 13 septembre 2018 par Carnet de la Bibliothèque nationale

Comments are already in favour of that third option:

Perhaps the simplest answer for Quebec is on the Wikipedia page for Maurice Duplessis "His era was later labeled as La Grande Noirceur ("The Great Darkness") by its critics."
_{– @sempaiscuba}

And that seems very plausible, although the first two were certainly not suited to lighten things up.

For Alberta it was something more direct:

Canada’s first, and perhaps most famous, legal case on free speech dates from 1937. In that year, the Alberta Social Credit government passed the Act to Ensure the Publication of Accurate News and Information, as part of a major legislative package to regulate the provincial economy. In effect, the law would have required newspapers to disclose their sources, name their writers, and print government-supplied “corrections” of any critical coverage. Papers that violated the law could be punished with a large fine and a ban on publishing restricted information. The Accurate News and Information Act was unquestionably the most blatant peacetime attempt to gag the press. In 1939, the Supreme Court of Canada found that the law was ultra vires (beyond) the powers of the Alberta government, ruling for the first time that provinces could not unilaterally restrict fundamental freedoms. Justice Lawrence Cannon accused the provincial government of imposing a doctrine that “must become, for the people of Alberta, a sort of religious dogma of which a free and uncontrolled discussion is not permissible.” [Alberta Press Bill, 1938] Writing one of Canada’s most cited legal decisions, Justice Lyman Duff argued that “even within its legal limits, it [public discussion] is liable to abuse and grave abuse, and such abuse is constantly exemplified before our eyes; but it is axiomatic that the practice of this right to free public discussion of public affairs, notwithstanding its incidental mischiefs, is the breath of life for parliamentary institutions.”

–– Canada's Human Rights History: Home > Encyclopaedia > Events And Issues > Censorship

How appropriate is this classification into this map? I'll enjoy comments on that one.

Could this be about anything other, like 'race'? When the US and especially the South is yellow? South American Countries or the Baltics already were independent and were 'just' in turmoil or getting another round of military coups or dictatorship.

We see a single one black communist/socialist dictatorship in the Soviet Union. With its leader Stalin indeed being the very odd one out and about touching the Arctic circle. All other black countries are right-wing 'civil' governments or military dictatorships. Like the full-on Vargas-Era one in Brazil. The most prominent leaders of those countries being cowered together into the lower right corner of the picture.
The grey areas are mostly European colonial 'possessions', like in Africa (Ethiopia an exception, but under Italian onslaught), or Asia (British India and Burma).

Now what exactly is it, that "it could happen here", in North American Canada?

That it's really mainly about creeping censorship, and through this lens how authoritarian regimes suppress freedom, by controlling the press, is shown for the other cases:

Most Central American and Caribbean dictatorships were brutally repressive and able to curb most forms of overt protest, providing very limited political opportunities for social movements and forcing most opposition to remain hidden and organize covertly (Bulmer-Thomas 1987). For example, repressive policies were characteristic of the Ubico regime (1931–1944) in Guatemala who regularly tortured and killed political opponents, and signed several laws which would condone executions of laborers by landowners as a “disciplinary” measure (Grieb 1979). In Hon- duras, the government of Tiburcio Carías Andino (1932–1949) restricted civil liberties, created a secret police, and started a campaign of censor- ship and repression against any opposition (Meza 1985; Dodd 2005). And in Nicaragua, Anastasio Somoza assassinated Augusto Sandino and 300 of his followers in Wiwili, used the National Guard as a spy network, and persecuted and killed any popular social movement that opposed his political power (Walter 1993).

In contrast, some Southern cone dictatorships – though still repressive – were more permissive towards social organization of workers and peasants. This resulted in more opportunities for mobilization and patterns of repression and accommodation that sometimes led to the fall of dictatorial regimes. In Uruguay, for example, the short-lived dictatorship of General Terra (1933–1938) could not effectively repress a series of general strikes organized by the labor movement; this created enough pressure to make him call for elections that resulted in a more liberal government lasting through the 1950s (Korzeniewitz 2000).
_{–– David G. Ortiz: "State Repression and Mobilization in Latin America", in: Paul Almeida & Allen Cordero Ulate: "Handbook of Social Movements across Latin America", Springer: Dordrecht, 2015. (p45)}

Venezuela: Eleazar López Contreras reintroduced censorship in 1936

India:

Provincial Autonomy (1937–1939) and Free Speech Controversies Issues of free speech continued to be important after the grant of provincial autonomy (in keeping with the Government of India Act of 1935)… In late December 1937, the (now Congrees-run) UP government issued a a statement warning political activists not to use 'irresponsible language'…
_{–– Devika Sethi: "War over Words: Censorship in India, 1930–60", Cambridge University Press, 2019. (p40)}

Which of course resulted in a little bit more critical voicing allowed than under British control, but still ample censorship of the press.

Burma:

The Official Secrets Act was passed in 1923, which makes it unlawful for any person to possess classified information from the state. A decade later, the Burma Wireless Telegraphy Act was passed, criminalising possession of telegraphs without government permission.

And of course more than just that.

It is often assumed that censorship was not used to any great degree by British authorities in Burma. Yet, by looking at the way the British colonial government reacted to a variety of media including traditional Burmese drama, western blockbuster movies, and Burmese political pamphlets agitating against colonial rule, it is possible to see that censorship was very much a part of the British administration. British authorities censored pamphlets, books, dramas, and movies not only to contain political thought contrary to colonialism, but also to control the image of British officials as seen in the eyes of the Burmese.
_{–– Emma Larkin: "The Self-Conscious Censor: Censorship In Burma Under The British 1900-1939", The Journal of Burma Studies, Volume 8, 2003, p64–101.}

French West-Africa:

B. Ọlatunji Ọlọruntimẹhin: "Education For Colonial Dominance In French West Africa From 1900 To The Second World War", Journal of the Historical Society of Nigeria, Vol. 7, No. 2 (June 1974), pp. 347-356.
Fred I. A. Omu: "The Dilemma of Press Freedom in Colonial Africa: The West African Example", The Journal of African History, Vol. 9, No. 2 (1968), pp. 279-298.

Lithuania:

In April, Christian Democratic newspapers, which had been calling for new elections, were censored. On 2 May 1927, Christian Democrats withdrew from the government, thinking that the Nationalists acting alone would not be able to sustain it. As a result, the Lithuanian National Union took the upper hand in its dispute with a much larger and influential rival and assumed the absolute control of the state. The 1926 coup was a major event in interwar Lithuania; the dictatorship would go on for 14 years. In 1935, the Smetona government outlawed the activities of all other political parties. –– 1926 Lithuanian coup d'état

Estonia:

In 1930, a law on a state of emergency was enacted that gave the Chief of Interior Defence extraordinary rights, including the introduction of pre-publication cen- sorship and confiscation of printed matter (Riigi Teataja, 1930, p. 749). Under this law, a state of emergency and pre-publication censorship were declared in the summer of 1933, when the political crisis reached its climax.
_{–– Epp Lauk: "The Rocky Road towards Professional Autonomy: The Estonian Journalists’ Organization in the Political Turmoil of the 20th Century", Media and Communication, Vol 5, Issue 3, 2017, pp85–94.}

Latvia:

On the night from May 15 to 16, 1934 the Prime Minister Kārlis Ulmanis and Minister of War Jānis Balodis, fathers of Latvian independence, took power by a bloodless coup d'état. Parliament and Constitution were suspended, State of War introduced, all political parties banned and press censorship established.

Peru:

The primary concerns of the new Government were: to resolve the conflict with Colombia (peace was negotiated in May 1934); and to 'assuage' internal political agitation…

To that word "assuage", cf Susan C. Bourque & Kay B. Warren: "Democracy without Peace: The Cultural Politics of Terror in Peru", Latin American Research Review, Vol. 24, No. 1 (1989), pp7–34; Marvin Alisky: "Peru: Bolstering Reform through the Media. Latin American Media: Guidance and Censorship", Iowa State University Press: Des Moines, 1981, pp67–88.

The only weakness in this grouping would be the Baltics, as they really should be quite black?

Since it was disputed in another answer: why was Greece coloured black?

The 4th of August Regime (Greek: Καθεστώς της 4ης Αυγούστου, Kathestós tis tetártis Avgoústou), commonly also known as the Metaxas regime (Greek: Καθεστώς Μεταξά, Kathestós Metaxá), was a totalitarian regime under the leadership of General Ioannis Metaxas that ruled the Kingdom of Greece from 1936 to 1941.

Metaxas' policies such as the censorship of the media, the banning of political parties and prohibition of strikes copied contemporary European authoritarian regimes. As its far-right contemporaries Italy and Germany, the Greek State also had its political police force, the Asfaleia, based upon the Gestapo (its chief Maniadakis maintained a close relationship with Himmler on methods and techniques). The objective of Asfaleia was to secure public order.

Or perhaps about China under Japanese control? Look no further than the magazine that published the map itself, John Maloney: "Bow to the Sentry", Ken Magazine, 30 June 1938, p70.

Although that overstates Japanese control of China on the one hand and the continued control of the press before Japan 'went in':

–– Lee-hsia Hsu Ting: "Government Control of the Press in Modern China, 1900–1949", Harvard University Press: Cambridge, 1974. (archive.org)

If any medical/psychiatric diagnosis would go by a democratic majority consensus vote, then having a democracy or allowing freedom of speech was 'the crazy idea' in the 1930s…

In any case, this map is referencing another map attributed to Carl William Ackerman, as a tiny bit wrongly explained in the quote in question.

Q Of note, Cotton has adapted and satirized Deal Carl Ackerman's contemporary "map of the black plague in the 20th Century" for this work

First Dea_n of the newly established graduate School of Journalism program at Columbia University Carl Ackermann familiarised an American audience with the concept of censorship being the contagiously spreading black plague at the time.

In 1938 Carl Ackerman, the dean of the Columbia University Graduate School of Journalism, said,

If the Black Plague spreads to the United States, newspapers will be controlled by the Federal government, and this school's functtion will be to train agents of propaganda and enlightnment, teaching its students to recognize only that aspect of truth which is authorized by a central government.

_{–– St John III Burton: "Press Professionalization and Propaganda: The Rise of Journalistic Double-mindedness, 1917-1941", Cambria Press, 2010. (p127) Referencing: "Ackerman Calls for Action to save Freedom Of The Press", Editor & Publisher,January 8, 1938, 5."}

This is on the originally published map in Ken, the magazine, which itself

was investigated in 1938 by the House Un-American Activities Committee for being Communist leaning. However, its editor Arnold Gingrich denied that the publication had any political slant. Seldes maintained throughout his life that "To these people [i.e, people like the House Un-American Activities Committee under Dies and later the McCarthyites ] 'one step left of center' meant 'leftist,' and 'leftist' meant 'red,' and 'red' of course meant 'Communist'" (despite that when Seldes was cleared by McCarthy, the press did not report it).

By the way: The backside of that map has this picture, fully in line with being just 'so 1938':

^_(src)

Being under such an investigation from the Committee on Un-American Activities is then of course a wonderful opportunity for Ken's publisher Arnold Gingrich to point out what his concern was all about. That anti-fascism is the liberal thing to do, not identical to communism:

I would like … to point out that democracy in America is now on the defensive,” Gingrich said. “Anybody who can read without moving his lips realizes that democracies at the present moment are showing what looks like a case of sprained, if not a broken, back.”

Gingrich went on to offer the committee evidence, gathered in the course of reporting pieces for Ken, of fascist activity in the United States.
_{–– Committee report pp 1221–1238. Also found here: Rebecca Onion: "Dark Satirical Maps from a Depression-Era Anti-Fascist Magazine", The Vault, Slate Magazine, 17 May 2017.}

That conservatism is just a slightly lighter black on its way to fascism isn't a new concept though. In 1934 Great Britain's Labor party already used the same metaphor. (Cf R. J. B. Bosworth: "The British Press, the Conservatives, and Mussolini, 1920-34", Journal of Contemporary History, Vol. 5, No. 2, 1970, pp. 163-182.)

The original map in question is now held at David Rumsey Map Center Stanford (where it was contributed to by George Grosz, the German painter who captured Goehring as a giant c**k) and at Cornell University Persuasive Maps: PJ Mode Collection.

The Ackerman map was published in the New York Times 3 Jan 1938,

and reprinted for example in January 27, 1938, Lincoln Journal Star from Lincoln, Nebraska, 5:

The Washington Evening Star from 7 Jan 1938 has a similar text as well, but alas not the image:

Carl W. Ackerman of the Columbia University School of Journalism. […] On Dean Ackerman's map there are much larger black splotches than on any of the other maps. He is trying to portray the prevalence of a relatively new disease, probably far more serious than any of those taken into account by Dean McKinley. His black splotches cover the whole of Russia, China. Japan, Siam, Arabia, Ethiopia, Libya, Egypt, Turkey, the Balkans, Italy, Spain. Portugal, Morocco, the Gold Coast, Angora, Mozambique, Yugoslavia, Brazil and Guatemala. There are also gray splotches indicating the areas into which the disease is spreading. These cover India, Burma, Lithuania, Latvia, most of Central America, Cuba, Ecuador, Peru, Bolivia, Paraguay, Quebec and Alberta. Dean Ackerman labels his disease "the black plague of the twentieth century.” It is the abolition of the freedom of the press by governments.
_{–– Evening star. [volume] (Washington, D.C.), January 07, 1938, Page A-8, Image 8}

Clearly, Cotton took the entire theme and actual map info and added his info-graphic and cartoon, for the general theme of his publishing intents, without adding much in terms of re-colouring areas.

The areas comprising this new Black Plague clearly encompasses more than half of the world. This wonderful drawing shows all of the characteristics of a pictorial map […], as well as Hornsby’s categories of pictorial maps showing amus*m*nt, instruction, place, industry (i.e., the military/industrial complex producing the weapons shown on the left), and the impending war and predicted postwar world if the dictators are not stopped.
_{–– Nick Kanas: "Star Maps. History, Artistry, and Cartography", Springer: Cham ³2019. (p435)}

The map colouring is not just some crazy leftist's imagination.

Although those areas that are coloured yellow certainly would need a re-evaluation by today's standards, as the do show some moral bias.

For example in Britain there was a certain 'freedom of the press', but it was for sure not free of censorship. The newspapers may have had some licence compared to other parts of the world but under the guise of morality and decency all media was subject to being called to be censored, like Joce's Ulysses or Virgina Woolf… This is examplified thusly:

People in inter-war Britain knew little about sexuality, in part because of censorship policies and the legacy of previous censorship cases that discouraged the circulation of knowledge. Men and women did not have an adequate vocabulary to describe their own bodies, let alone the opposite sexes or the acts that bodies could perform. People lived in a culture of ignorance. Thousands wrote to Marie Stopes, the noted authority about sexuality, for information about birth control, abortion, sexual problems and sexual practices. The lack of information about these matters made bad conditions even worse. One infantry officer, unable to find basic birth control information, never consummated his marriage: “I have been married for nearly a year, but owing to the fact that I have been serving as an infantry officer in France, + having therefore a somewhat uncertain tenure in this world, our marriage has yet to be consummated.”103 He feared he would leave his wife pregnant and widowed. Another man's letter illustrates the ways that any information might have been useful. “We are both self-taught in the matter. To be candid for the first 4 months of our married life I did not know that it was necessary to move my body in any way. We only know of the one positions (sic) in which my wife is underneath + I am sure I nearly smother her sometimes. Now can you tell me of alternate positions + also is my wife supposed to move about?” Obscenity might not provide the best education on sexual matters but any information would have been better than none. Such small, sad stories illustrate the consequences of censorship; though state policies remained hidden, they still resulted in real suffering.
_{–– Lisa Z. Sigel: "Censorship in Inter-War Britain: Obscenity, Spectacle, and the Workings of the Liberal State", Journal of Social History vol. 45 no. 1, 2011, pp. 61–83.}

Such preoccupations reflect the centrality of important questions of political authority, economic crisis and escalating conflict to interwar historiography, the enduring power of national historical traditions, and constraints of sources and language. The centripetal tendencies of institutional histories of the press and an emphasis on the specific local contexts in which newspapers operated might similarly work against a systematic transnational comparison. The impassioned claims to press freedom voiced from Fleet Street and the power and personal influence of press barons like Beaverbrook and Rothermere in Britain, to take the most obvious example, provide sharp contrast to the forms of censorship and control elaborated in the emerging continental dictatorships.

Through a close and careful analysis of the office records of newspapers in Germany and Italy, she draws attention to the striking influence of changing state policies on journalism and commercial advertising on the format, tone and content of German and Italian newspapers. Drawing on the office archives of popular journals like Frauenwarte and Il Popolo di Roma, Gaudenzi traces the everyday interventions and influences of officials from government departments like the Ministry of Popular Culture in Italy on the decisions made by journalists, editors and proprietors. Such interventions, she suggests, marked a growing collusion between the state and the professions of advertising and journalism* most evident in the ways in which official policies towards womanhood and consumerism began to pervade the popular press in both Germany and Italy. Through such interventions, Gaudenzi suggests, the boundaries between state and market collapsed. Yet the politicisation of the press was a feature of Europe’s democracies as well as its dictatorships. In Britain, for example, even the royal household employed a professional press officer between 1918 and 1931 in order to cultivate public opinion and sell what was often perceived as the fragile and anachronistic institution of monarchy to a modern mass democracy. There and in France, political parties sought to use the press to engage an expanding electorate. Whether debates around the power of the press coalesced around the influence of censorship and central control in the Fascist powers or the growing power accrued to the press baron within the capitalist marketplace, the concerns were broadly the same (Curran and Seaton 2003; Forgacs and Gundle 2007).
_{–– Sarah Newman & Matt Houlbrook: "INTRODUCTION", Journalism Studies, 14:5, 640-650, 2013.}

This kind of map gets produced quite regularly. One of the latest runs quite interestingly against a few grains.