Actually, at it's core there is a valid arguement here. The stupid part is the allegations of racism, which fall under free speech if they are even present in the movie (I haven't seen it to comment on it), however trying to pass a product off as something else is illegal, with the practices of advertisers and the like coming under increasing amounts of fire in recent years. It's not surprising that those selling intellectual properties would be held similarly accountable, for leading people into thinking a movie is one thing, and giving them something else. It's no differant on a fundemental level than say selling someone chocolate candy, but actually putting sugar cubes with food coloring inside the product or whatever.
Given that movie makers have been caught using deceptive practices through the years to sell movies, cutting together differant scenes out of context to imply something that doesn't actually happen in the movie, or using footage that has wound up on the cutting room floor (a semi-famous example would be a scene featuring Mel Gibson and a dog from the movie "Payback" that was in the trailer but not in the movie) and so on.
You can say what you want about the brainless mass of movie goers, but there is a valid point that if your going to see a mindless car chase movie to put your brain into neutral, being handed a drama that doesn't fulfill that promise is an issue.
I think back to the movie "Fight Club". The movie has become something of a classic, but it was a case where the trailers for it were intentionally misleading. Those going to see a martial arts/cage fighting movie were given something else. In that case it paid off, but really I was kind of surprised they hadn't been successfully sued by someone especially seeing as I remember them flat out admitting that they set out to trick movie goers because they didn't think your average schlub would have given that movie a chance if they had known the actual premise of the film. As it is now, with the reveals out, there are those who refuse to watch it due to the "stupidity of a movie about a guy beating himself up" (which might not do justice to the entire film, but that very reaction is exactly why they did what they did).