> Part of the beauty of The Twilight Zone, as a science fiction show, was that Serling could get away with social commentary by disguising it as harmless fantasy. He was allowed to be critical if he was allegorical at the same time. As he himself put it, "You know, you can put these words into the mouth of a Martian and get away with it."
Presumably someone who's not PC could use allegory to get away with being un-PC.
Think of Joss Whedon's Firefly, in which the Alliance is a thinly-veiled allegory for the triumphant Union shortly after it destroyed the Confederate States.
http://www.plosin.com/beatbegins/projects/brenner.html