The problem with the conversation surrounding the Family Guy episode is that it presupposes that people fall into one of two categories: those who think the joke was funny because they weren’t offended by it, and those who think the joke wasn’t funny because they were. I didn’t find the joke funny, not because it was insensitive to people with Down syndrome or to Sarah Palin, but because it just wasn’t funny. Like, as a joke.

Alston, in re MacFarlane v. Palin (via newsweek)

Yup - that pretty well sums it up.