I tried that before they were 13. Technically false, but almost no social media company allows under 13s.

It didn’t work very well.

Whether experts have determined it's not healthy is independent from whether it's against the law.

Whether it's the rules of the parents, or the "rules" of the government, they're all the same in the eyes of a child.

source: was once a child

A true observation, but not sufficient to criminalize and infringe on basically everybody else.

There are all sorts of things that would be easier for parents to prohibit if the government made it illegal: Popular toys, M&M's, pork, anything that questions the bible...