Because calling people fat isn\'t funny. To me comedy is at its most funny when the comedian has the moral high ground. Then he can say pretty much whatever he likes, and it can be amusing, and its at the expense of the bad guy/s. Take my example of Russell Howard. When he was satiring racism, he was pretending to be a member of the EDL, and as the News interview showed, that\'s the sort of level a lot of those people are on. That\'s ok, because the moral high ground is showing that racism is stupid. If he were being racist to be funny, that would not be moral.