I mean, they're steeping in environments online that aren't really very age-controlled. Log into any free-to-play or public server game with voice chat and give it a listen. It's just a bunch of literal small children screaming racial slurs. They might not all be in environments like that, but enough of them are that it's definitely going to substantially alter their experience.

They have a level of practical autonomy that we couldn't have dreamed of with little to no oversight that at this point is decades entrenched. Outside of adult-only spaces the Internet is basically Children of the Corn. Even the ones who aren't wrapped up in that nonsense have to contend with the ones who are, and none of them are going to have the emotional maturity to really deal with it properly.

How could we not expect rude children who grow up to be callous protofascists and narcissists?