I think the Simpsons is not racist is simply because racism is predicated on the idea that one race is superior to another. It may take the form of hatred and exploitation, paternalism or simply the idea of intrinsic, essentialist notions of race. The Simpsons doesn't really have this, at least as far as I've noticed, because it protrays everyone, of every race, as equally as stupid, or at least flawed in some way, as well as being equally notable or even good in some way. In fact, it has made fun of the more 'harmless' of the racial essentialist ideas, such as the ones protrayed by TV comedians who talk about the different way blacks and whites drive.

The only thing that the Simpsons could be seen to promoting is nationalistc sterotypes, and, again, I really don't see that as seperate from the whole make fun of everybody thing. I mean, as dbrown noted a lot of these are sterotypes, and while they are a crutch in the real world, they may be appropiate for comedy. It's a just a matter of perspective and aplication, and the right nose for what is funny, and what is offensive.