The article seems to say "back when I was a kid, my parent entertained me with contentless saccharine trip from sources we trusted (Disney et al) but now contentless saccharine trip is autogenerated (duh duh duh) and who knows what effect that is going to have on 'developing brains'"
And would suspect, contrawise, that if there's a problem, it began at the point when the TV became the primary babysitter for modern children and things escalating to youtube is a step but a less significant step than this.
Edit: OK, the complaint is video moving from simplistic saccharine junk to the same thing with violence. I get that this is the step that disturbs parents lazy/busy enough to consign child rearing to video but controlling enough to think kids will parrot whatever they see. I would still see consigning kid-hood activity to video as where the damage comes. But maybe "that's just me"