That seems like circular logic.

You're saying parental responsibility should govern because TikTok is legal, while cigarettes require state intervention because they're illegal. But they are only illegal because we made them illegal (for minors). And isn't that exactly what is being discussed here?

For the sake of consistency, do you think cigarettes should be legal for minors if they have parental consent? If not, what is the distinction between TikTok and cigarettes that causes you to think the government should be involved in one but not the other?