That's great, feel free to supervise your kids. You don't get to use the government to do it. Are you saying that the 1st amendment can have exceptions if a child's safety is at stake?
Oh but we do. Kids have been prohibited from entering bars and buying tobacco, by law for a long time. We generally think that's a good thing, and why it continues to be law.
Yes, the Constitution limits state govts as well, a slight misstatement written in a hurry.
Your obtuse pedantry is not useful. Particularly when it appears you still have missed the main point of the previous statement—that the Constitution limits government, not citizens.
Also, these laws restrict children, not adults as you're suggesting. Basically this whole subthread is irrelevant. Good day.