I think it's hilarious because it's so over the top, but I think they're trying to argue against violent cartoons too (in a strange way).

I like the fact that the Simpsons almost always shows Bart and Lisa's reaction when Itchy and Scratch is on. It gives me a slightly creepy feeling to see the kids having such a good time watching such gruesome violence. I can't help but feel they're trying to let people know that children are affected by such things.

Scratchy always comes back, so that mitigates it a little.