Children are dependent, so they must be controlled by parents. It is parent's respossibility to supervise their kids behaviour and mainly to help children not to go wrong way. Don't count on that children can judge every thing in the right way.
We her have a chinese kids who are very rebal, He think that human life is short and enjoy is the first preprioty. He touchs drug sometimes and basic not doing shool study. I don't think any parent here can tolarent to that.