The writer (and lunatic) Philip K. Dick was told of a close friend's cancer, and he started laughing because, he said, he couldn't think anything funny about it--humor was his defense mechanism. I can think of many situations where I found the way to an answer for a problem but making fun of the problem.
Humor isn't this "low class" thing left on the porch when we go inside; it's the sharpest tool of the sharpest minds. And no, "crude" humor isn't left out. Just because someone is being crude doesn't mean...well, what DOES it mean? Why is someone offended when someone mocks something you take seriously? Only that they find something funny about it. Doesn't mean they want someone to die, or think someone is inferior, or whatever, and are just too scared or cowardly to admit it--it MIGHT, but it doesn't have to, no more than some of the people who post incessantly in "respectful" ways about Terri Schiavo want someone to die (Michael), or think someone is inferior (Judge Greer) or whatever, and are just too scared or cowardly to admit it.
Humor--crude, disgusting or whatever--is a legitimate form of discourse. Those who say "That's not funny!" because someone ELSE thought it was funny have some soul-searching to do, I think; it reveals a bit more about him or her than one might think.
On another thread I was castigated by bluenoses for humor in "poor taste" and although I haven't seen this South Park episode, I am always amused by people who think there are some subjects that cannot be treated with humorThe only morbid topic of the last twenty years that AFAIK never generated any jokes was 9/11. Everything else seems to have been "on-limits", so to speak. Morbid jokes have replaced "dirty" jokes in our culture.
Certainly the over the top histrionics associated with the Schiavo case, from "they're going to kill all the disabled people" to "starvation is wonderful" have made it a natural South Park target.
Indeed, the last page of Kenny's will, when found, was spot-on.
-Eric