Good piece by Dennis Cozzalio.

Originally posted by Chris Knipp
I think the film has kitsch aspects but probably people and critics misread it as something tacky when it was serious, due to its link with blaxploitation and the way in which it was marketed.
Well, subtle it ain't. It's in-your-face and never "politically correct". It's practically impossible to misinterpret what the film reveals about the nature and implications of slavery for all involved. No other film I've seen had the courage to display it with such clarity. It was marketed as a piece of populist entertainment and it worked. The film did well at the box office despite many critics not reviewing it or having a generally unfavorable opinion of it. Kitsch aspects? Definitely the overemphatic, often incongruent music score by Maurice Jarre.

I don't think we can assume that the critics met the film with "derision" because it made them uncomfortable. My guess is that they either didn't see it or didn't perceive it accurately at all. I don't agree with you that being made uncomfortable automatically arouses a response of derision.
I don't either. To clarify my position. I think the content and presentation would make a significant number of people uncomfortable or anxious. A common response (but not an automatic response and not the only response) to something that makes people uncomfortable/anxious is to treat it as an object of derision or ridicule.