How do you make sure that whoever makes that choice makes it in a way you yourself will agree with?
People's lives are ruined by gambling all the time, for instance. It is dumb to pretend like the pleasure a few people get out of it is worth someone betting away his family's welfare. It is ok to just decide "this needs to be regulated." Not everything is some intractible philosophical mystery that no consensus will ever coalesce around. Not every single thing every single person wants needs to be taken seriously.
If you're going to get philosophical, go all the way. Why have society at all because it's just people imposing their will on others? Or do you at least agree that there exists a line?
It’s not at all obvious that “adults can’t have TikTok” is anywhere near the correct side of that line.