Upvote:6
Like most quotes, context is quite important. Taking a single line out of context makes understanding it more difficult. You can find multiple references to illness in the same I've Been to the Mountaintop speech. (I will cite from the copy linked to by the Wiki article found at americanrhetoric.com. As usual, all emphasis mine)
the world is all messed up. The nation is sick. Trouble is in the land; confusion all around.
and here
that Memphis is not being fair to them, and that Mayor Loeb is in dire need of a doctor.
and finally here
And then I got into Memphis. And some began to say the threats, or talk about the threats that were out. What would happen to me from some of our sick white brothers?
When taken in context with the other connections in the same speech, I think it is clear that we can eliminate concern for Mayor Loebs' physical health.
The illness being metaphorically referred to was the same that MLKs' civil rights struggle had been fighting all along; injustice, discrimination, racism.
This interpretation can be found published in other sources:
from Martin Luther King Jr. and the Sermonic Power of Public Discourse, 1993
Another work, The Scourges of the South? Essays on βThe Sickly Southβ in History ... points out Kings' connection to author Lillian Smith, who held similar views about racism: