Dang, this is definitely a hard topic to pick a side on... well, I've long thought that the acceptance of comedic racism is actually a good gauge for how much racism there is in society--as long as no one's going overboard or, as TEM said, going beyond a joke into mocking malice, not getting all uptight and offended at a racial quip indicates that at least one person has learned that it's okay to laugh at this or that culture or creed's idiosyncrasies and still not be a bigot. It's for this reason that I think Al Sharpton et al really do seem to actually bring black people down when they pick the pettiest of issues to complain about.
On a related note, I'm not sure if it's really a racist joke--perhaps the polar opposite, in fact--but that episode of South Park with the guy on Jeopardy posed with "People Who Annoy You" is perhaps one of the funniest things I've ever seen.