Why Do The South Park Guys Hate All That's Good and Decent?

A little late, but to add to my collection of nasty quotes about Family Guy, here's one from an interview a couple of months ago with Trey Parker and Matt Stone of South Park:

What's the meanest thing ever said to you before, during or after a gig?
MS: When people say to me, “God, you guys have one of the best shows on television. You and Family Guy.” That fucking hurts so bad.
TP: Very well said. It's such a kick in the balls.

Maybe if I find enough quotes like that I can assemble them into the inevitable "Why I Hate Family Guy: The Book." Somehow I feel it's needed at this moment in history.