Parents are not encouraged to give children unlimited access to alcohol or tobacco or hard drugs. Sure, they might find ways to break the rules, but are those rules then completely useless? Plenty of teenagers will claim that the rules just caused them to rebel, when in reality the rules were mostly effective and the teenagers are criticising a system from a sample size of 1 with no control.

This "rules are bad" is just silly. Kids aren't perfect and not every flaw is due to the parents making an egregious mistake - often the actions of parents are ones that make children into better people. It's also telling that the archetypal advocate progressive "child-centered" education (where natural consequences are good but authority is bad) was Rousseau, who never raised children himself.