Well, I think treating hatred that actively harms other human beings as a joke is insensitive and horrible.

And it's important to distinguish that sort of thing from humor at the expense of the haters; see To Be or Not to Be, The Producers, and Hogan's Heroes (in the last, all the major Nazi characters were played by Jewish actors, some of them Holocaust survivors or escapees, who relished such an opportunity to caricature their oppressors.)