I believe that responsibility lies both with parents, for failing to adequately control their kids's behavior and teach them the basic rules of coexistence in society, and with the kids themselves, as they cannot be exempt from blame.

But if no action is taken, the problem will only get worse. When I was a kid, my parents knew exactly where I was, what I was doing, and who I was with at all times. Because they knew that if I got into trouble, it would affect them in one way or another. That's the kind of responsibility all parents should have toward their kids. It is a complex issue and each country tends to approach it differently, but this is my opinion on the matter.