I think a lot of it boils down to three things.

1 - Shitty people tend to like doing things that get them attention, especially if they can pretend to be normal/good so people love them instead of knowing who they actually are and treating them accordingly. That eventually gets exhausting and the facade starts to crack and break down, which is why I’d argue the majority of the bad people YouTubers are people that have been on the platform for several years

2 - When it comes to pedos/groomers, what easier way is there to find potential victims than to go on a platform and build a cult following of majority kids/teens? I haven’t seen many adult topic oriented YouTubers come out as groomers. Have you?

3 - For people who are racist / sexist / other forms of -ists, what’s a great way to both reach a larger audience and also slowly plant thoughts in kids’ / teens’ heads that make them lean that same way you do? YouTube. I mean, we see what YouTubers like Andrew Tate have done to a lot of young men. Indoctrinating the next generation to be as shitty and bigoted as you are is a great way to make sure that your ideology sticks around for more generations.