It is a collective responsibility. But the problem is that a lot of parents have come to see their children as personal possessions. Possessions that others need to leave alone.

I remember as a kid that adults of any sort could correct you. You didn't talk back either. If you did and your parent(s) found out, you got it good when you made it home. Bad behavior was rewarded with punishment of some sort. And it could be dished out by any well meaning adult.

Nowadays, God forbid you correct another's child if they are behaving badly.