Then a logical question would be...why shouldn't anything go, in either situation? That's what free speech is supposed to be all about. It's one thing to say that such materials are wrong, that they should all be criticized and that far more constructive alternatives should be promoted, but personally I don't believe in thought crime nor in legislating morality and thus can't consciously condone the banning of any book, movie or game, no matter how sexist, criminal, disturbing or despicable in subject matter.
At the same time, I fully respect and salute the right to protest against such offensive materials, as that is also a part of free speech and I do believe it is morally justified to oppose them, but banning just cannot possibly be the real answer as far as I am concerned.