As a teenager myself, I believe this could be because when we are teens, we tend to be more risky. Teens are usually known as risk takers.
Knowing this amplified the chances of so many teens getting restrictions, mostly because parents do not want their teens going down bad paths in life, or messing up their future.
As for laws, many of us are too young for certain things without a doubt. Some of us can handle certain things, some of us can’t. Perhaps it’s to make things easier?
But yes, I do believe teenagers do have a lot of restrictions. At least there is adulthood to look forward to!