So, almost all American teenager comics feature superheroes and lots of gruesome violence? I wasn't sure about that, but it is strange. European comics (or at least the ones here in the Netherlands) are totally different. They mostly feature more or less normal people doing interesting or absurd things. While some are completely over the top, there is very little actual violence in them. Almost nobody ever gets killed. And if that happens, it's more like a detective story.
In those superhero comics, the limbs, heads and intestines are flying around, skeletons are everywhere, weapons have to be many, bigger and better, and forces have to be as destructive that they at least could destroy the whole Earth. And they are mostly about being all-powerful, to better be able to cut the bad people to pieces, in graphic detail. Doesn't that get boring and gives teenagers strange ideas about values and entertainment and such? Most parents around here would forbid their sons to read those superhero comics when they take a look and see what's inside.
The older ones can be quite entertaining, but the ones from the last few years are just sick. Although YMMV.
Dunno, but I think it is quite weird, when you think about it.