Do you remember being a child? Were your parents strict? Mostly of you would say: Yes, of course. And it had not changed even a little. Parents like and have to feel control of their offspring.
You were always considering why parents do not agree you to drink or smoke. The answer is simple and prudent - it is unhealthy. This is right but are extreme sports also unhealthy? No, this is dangerous. What about meeting your friends lately? This is neither unhealthy nor dangerous so why is it forbidden for us? All adults drinks, smokes, does extreme sports and a lot of other activities which are risky and does not make them healthier. What is the point then? Maybe they feel they are better, more experienced or wise than we are, children and teenagers. This is all about their psyche. They must feel control.
Parents are not satisfied with their lifes.
They wanted to become rich and famous, unfortunately they did not. According to this they treat us like a thing, a doll which they can play with, conquer their own fears and repair mistakes from the past. They want to fulfill their own dreams, to achieve the pick of abilities and always be better. So we do, but parents want us to become lawyer, not doctor of football player instead of astronaut or singer. Parents say us to go to the school and later sit in home doing homework and self-developing. If we do not do that, they punish us. Parents ban for example using the computer, going outside to meet friends etc.
In newspapers we can read about teenagers who had roamed the street or bullied younger children. Why? Mostly this is parent's fault. The most exciting are the forbidden things, whatever it is. Even reading books may be risky but impressive if it is banned. When parents say: you cannot watch this film and play that game because it is too violent. Violence is banned then in any form. For child violence become unknown so it is something that the child thinks about with excitement of young explorer. Later the child starts to use violence and parents punish him for doing that. This causes more aggression. A kind of vicious circle.
Every action causes reaction. If parents are strict, their children will also be strict for their children, and so on. Seems it is unchangeable.