The people who make that stuff are all adults. Though, I guess people think thye're childish too.

People just don't treat video games as a media (thing). They treat it like a toy, for kids. Most of it's not. It's why people are so bothered by things like GTA- kids shouldn't be playing it. No, they shouldn't. That's why '18' in the big red letters? A lot of kids games are crap anyway.
And comics- Judge Dredd? Really kiddy. Nothing better for toddlers than fascist police states and all that spiff!