The first thing to notice about the posts linked to in the question is that neither of the theologians in the discussion is claiming that all taxation is theft. Rick Phillips explicitly says "there is a legitimate basis for government taxation". The WeeFlea claims that Sproul believes that "all tax is theft" (both from links in the question). But there is no such statement in Sproul's publicly available writings. The closest he comes is to write: "When a government takes from the people more than it takes to finance the legitimate God-given function of the state it is not just mismanaging, growing bloated, becoming inefficient—it is stealing.". There is a big difference between 'excessive tax is stealing' and 'all tax is stealing'.

Sproul's idea that 'excessive taxation is stealing' appears to derive from a belief that the legitimate actions of the state are limited by scripture. Since I know of no explicit scriptural restrictions on the state I assume that he takes the scripturally approved functions of the state as limiting; and that any actions not included in them must be prohibited, even if they are approved of by the people. It's an easy deduction from there to assume that collections of taxes to perform illegitimate functions is itself illegitimate.

The only group I have discovered that truly believes 'all tax is theft' is Christian Anarchists. Their theological basis may be summed up as:

Christian Anarchists believe that Christ is the one True King, and all earthly kings are usurpers. God nowhere commanded men to form "the State." Everything the State does is a violation of God's Law.

Foundations: Taxation and private property are in tension

The commandment (Exodus 20) "Thou shalt not steal" implies the right to private property, and this is everywhere assumed in Scripture (even in Acts 5). If princes had the unlimited right to tax, to any extent and for any purpose, there could be no private property. All would belong to the state, or to the prince personally. Since this is not so, there must be limit to the allowable extent and purpose of taxation.

Augustine on the affinity of kingdoms and robbers

One of the bloggers quoted in the question, likens taxation to the behaviour of a highway bandit:

So are taxes theft? Absolutely. We submit to paying those taxes only because the consequences of not paying them are worse. This is no different than a highway bandit that positions himself at the beginning of a route and demands all passers-by pay a toll in exchange for "safe passage" along the road.

This comparison is not new.

In the fourth century BC there lived a notorious pirate who ravaged and plundered many coastal towns. At last he was captured and brought before the emperor Alexander the Great, who granted him permission to speak, prior to condemnation. The pirate's reply so impressed Alexander that he not only didn't punish the pirate, he even gave him enough wealth to live comfortably, and peacefully, ever after.

More than 700 years later, St Augustine quoted the story of that pirate in Chapter 4 Book 4 of his City of God. "How Like Kingdoms without Justice are to Robberies."

Justice being taken away, then, what are kingdoms but great robberies? For what are robberies themselves, but little kingdoms? The band itself is made up of men; it is ruled by the authority of a prince, it is knit together by the pact of the confederacy; the booty is divided by the law agreed on. If, by the admittance of abandoned men, this evil increases to such a degree that it holds places, fixes abodes, takes possession of cities, and subdues peoples, it assumes the more plainly the name of a kingdom, because the reality is now manifestly conferred on it, not by the removal of covetousness, but by the addition of impunity. Indeed, that was an apt and true reply which was given to Alexander the Great by a pirate who had been seized. For when that king had asked the man what he meant by keeping hostile possession of the sea, he answered with bold pride, 'What you mean by seizing the whole earth; but because I do it with a petty ship, I am called a robber, while you who does it with a great fleet are styled emperor.'

Augustine identifies two key concepts: justice and impunity.

• Impunity: The practical difference between the highway bandit and the government is that the government feels certain it can get away with it, whereas the highway bandit lives in some fear of being caught and punished. The ISIS-controlled regions of Syria illustrate today the process Augustine refers to by which bandits become princes.

• Justice: The moral difference, which may or may not apply in any given case, and which Augustine refers to in his opening sentence, is justice. Taxation to provide justice is distinguished from simple extortion for other purposes.

According to a modern scholar, to Augustine "government serves an essentially negative function—to restrain and punish the wicked."

It can thus be argued that, just like the blogger, St Augustine believed tax is robbery, except when, and to the extent that, it is needed for justice.

The Lollards on taxation by unjust rulers

According to Schaff's account, in 14th century England Wycliffe, a priest sometimes called the Morning Star of the Reformation, said:

There is no moral obligation to pay tax or tithe to bad rulers either in Church or state.

During the Peasant Revolt (1381), resulting from King Richard II demanding a poll tax of a shilling per man, the Lollard priest John Ball, preaching to a vast throng gathered on Blackheath, near Greenwich in London, told them:

When Adam delved and Eve span, who was then the gentleman? From the beginning all men by nature were created alike, and our bondage or servitude came in by the unjust oppression of naughty men. For if God would have had any bondmen from the beginning, he would have appointed who should be bond, and who free. And therefore I exhort you to consider that now the time is come, appointed to us by God, in which ye may (if ye will) cast off the yoke of bondage, and recover liberty.

It is clear that these priests did not accept any moral obligation for the poor to pay taxes to subsidise the lifestyles of the rich. Even Archbishop Courtenay strongly attacked the extravagances of Richard II, a principle cause of the poll tax, for which he was temporarily exiled to Devon.

Mayhew on taxation without representation

In 1750 the Reverend Jonathan Mayhew preached a sermon in Boston which is sometimes cited as a cause of the American Revolution, or rebellion, against King George III. His slogan was "No taxation without representation". This maxim was not necessarily a universal theological principle, but was held to be a constitutional right of British subjects under the Bill of Rights 1689.

Mayhew preached on Romans 13 1-7 in which St Paul urges submission to the civil authorities.

This is also why you pay taxes, for the authorities are God's servants, who give their full time to governing. (verse 6)

Rev. Mayhew pointed out that St Paul had said tax was payable because of the nature of the authorities as servants of God devoted full time to government. He then went on to consider what he regarded as the quite different case, which St Paul had not referred to, where the authorities were not servants God, and were not devoted to good government. About that case, St Paul had said nothing.

"For, for this cause pay you tribute also; for they are God's ministers, attending continually upon this very thing." Here the apostle argues the duty of paying taxes, from this consideration that those who perform the duty of rulers, are continually attending upon the public welfare. But how does this argument conclude for paying taxes to such princes as are continually endeavoring to ruin the public? And especially when such payment would facilitate and promote this wicked design! "Render therefore to all their dues; tribute, to whom tribute is due; custom, to whom custom; fear, to whom fear; honor, to whom honor." Here the apostle sums up what he had been saying concerning the duty of subjects to rulers. And his argument stands thus—"Since magistrates who execute their office well, are common benefactors to society, and may, in that respect, be properly styled the ministers and ordinance of God; and since they are constantly employed in the service of the public, it becomes you to pay them tribute and custom; and to reverence, honor, and submit to them in the execution of their respective offices." This is apparently good reasoning. But does this argument conclude for the duty of paying tribute, custom, reverence, honor and obedience to such persons as (although they bear the title of rulers) use all their power to hurt and injure the public? Such as are not God's ministers, but Satan's? Such as do not take care of, and attend upon the public interest, but their own, to the ruin of the public? that is, in short, to such as have no natural and just claim at all to tribute, custom, reverence, honor and obedience? It is to be hoped that those who have any regard to the apostle's character as an inspired writer, or even as a man of common understanding, will not present him as reasoning in such a loose incoherent manner; and drawing conclusions which have not the least relation to his premises. For what can be more absurd than an argument thus framed? "Rulers are, by their office, bound to consult the public welfare and the good of society: therefore you are bound to pay them tribute, to honor, and submit to them, even when they destroy the public welfare, and are a common pest to society, by acting in direct contradiction to the nature and end of their office."

Thus, upon a careful review of the apostle's reasoning in this passage, it appears that his arguments to enforce submission, are of such a nature, as to conclude only in favor of submission to such rulers as he himself describes; i.e. such as rule for the good of society, which is the only end of their institution. Common tyrants, and public oppressors, are not entitled to obedience from their subjects, by virtue of anything here laid down by the inspired apostle.

​In recent history some people may feel that Hitler, Stalin, Pol Pot and others would have failed the Mayhew test as deserving of tax.

Disraeli on taxation as class warfare

Benjamin Disraeli, UK Prime Minster in 1865 and 1874-1880, said

To tax the community for the advantage of a class is not protection: it is plunder.

This is perhaps closer to the modern American argument since voters in a democracy are themselves princes, or princesses, and the question is not only whether they are bound to pay whatever tax is demanded from them; but also what rights do they have to demand (or support politicians who would demand) taxes from others. To vote for a politician who will plunder one section of the population to benefit another is, arguably, the same as to take part in such plunder oneself. Nor, arguably, is voting that someone else shall help the needy, a substitute for doing so oneself.