Previously, bad influences were limited to what your local neighborhood kids were telling your kid. This could be bad, they could be torturing cats or something, but that wasn't likely. And that floor could be raised by society as a whole improving.
Now, with TikTok, the only limit is what TikTok will ban. Which isn't much. The population segment of kids who aren't supervised in any way used to have an inherent limit. Not any more.
So I suspect there's not necessarily a decrease in parents keeping their kids from bad influences, and more that there's an increase in access to (and severity of) bad influences.
Edit: I should be clear, I want to minimize banning stuff as a solution as much as possible. I think the goal should be to move kids back into supervision and teaching by their parents, and just real people in their life. Parents, friends, educators, etc.
The problem is much of America (and much of the world) is completely boned on this front by living in places that just don't form a community, like suburbs, or just low-density non-walkable areas in general. Complicated by the fact that the vast majority of parents are getting non-work time squeezed out of them by increases in cost of living without any increase in pay.
Banning more stuff is the single-line-item solution, the simple way, the just-get-biden-to-do-an-executive-order way. But I would be horrified if that's all we could manage. I hope we can do the real solutions, not the deeply flawed patch that banning stuff is.