I've seen that millions of users have been blocked on wikia. Because of young age. Just why?

Probably this is the answer: Kids can't handle social media. Probably a stranger would harass you if you were a kid. Or many more.

I'm only 7 (DON'T BLOCK ME!). And I used to be bad. But now, The ultimate Peter now harasses the trolls and others. (Sorry, that has to do nothing about this blog post.)