Examples I know about include 12-year-olds selling nudes, teen experimentation with alcohol being replaced with cocaine because cocaine is so easily available (the issue is the scale and how widespread cocaine is getting; not that it never happened before), several cases in Norway of 13-year-olds being recruited by the mafia to throw bombs at houses through the internet, violence etc. is up the roof, kids have 4 hours of sleep since they doomscroll all through the night, results in school are trending downwards, university reports that students are increasingly unable to concentrate...
Are there other solutions than bans to social media? Sure. Could this in theory have been fixed by better parenting? Sure.
But parents don't live in a vacuum. Parents and children alike rely on the culture around them.
Social media is a HUGE shift to society, and neither culture nor parenting practices has sufficiently adopted to handle it yet. Slowing the shift down a bit until norms and culture catches up doesn't seem like a bad idea.