Why do some people hate Frankie Boyle?

I know some of his jokes are sick and he can be very offensive, but so can Nick Griffin and David Cameron. The only difference is that Frankie Boyle makes people laugh while being offensive. Besides, it's not like he's racist or homophobic or anything-he makes fun of everyone, from every race, country and he makes fun of HIMSELF. So why do people get so offended? He even says it himself-He's a comedian, on a comedy stage, it's always nothing but a JOKE.