Engagement on the internet is also being driven by neural networks that are learning to adapt to the users brain chemistry to statistically modify behavior for maximum engagement/profit. Perhaps it is time to realize that these services are going to be analogous to a random stranger offering your kid candy for their own twisted goals that are unlikely compatible with a child's well being. If you consider a service like YouTube as an untrusted source of interaction perhaps you'll be as likely to block or monitor it the same as random chat rooms.