dnovraD: I had a dark sense of humor when I was probably half my current age; to wit, there were various games like the Buddy on deviantArt which served to such dark urges.
This seems like that, but with an another layer of violence slathered atop.
Well, I never outgrew mine. Guess that's why I was still part-time referee for role-playing games at a local youth center well into my 30s. Their silly teenage antics gave me a great many laugh. I'd still be doing it if I still had the time.
My personal threshold in terms of comfort is when it gets overly realistic, but this is pretty cartoony so it is all fun and games for me.
I think if I really had to put a finger on it, it is our self-destructive irrationality that really tickles my funny bone. Whenever I see crazy over the top violence in fiction, I'm always very conscious of the fact that it was an artistic decision to make it so and that makes me laugh quite a bit.