There are good parents whose kids use drugs and engage in criminal behavior. Short of locking a teenager in a room, he/she will have opportunities to get ahold of drugs. A parent can send a child to rehab, but there is no guarantee that it will take. What do you do, then? I have known/seen good parents at their wits' ends trying to help and reform their children. People like you who attribute everything to environment operate on an 18th/19th century, blank slate belief system that has no basis in fact. When I state this here with regards to intelligence, criminality and other things, most go running and the others become infuriated. That's almost always a surefire sign that someone has struck upon an uncomfortable truth. Anecdotally, both you and I have known families where two kids turn out great, while the third habitually engages in deviant behavior, has addictions, and generally brings shame upon the family. That isn't environment. The parents didn't completely change how they parented with that one child. There are many things beyond environment that shape who we are and become, and how we behave. If you think parents have all the power to reform the behavior of 15/16/17 year-olds in our society, you are simply mistaken. In many cases, that kid is going to do dope, steal, assault, et cetera, in spite of all the efforts of the parents. This has been true since the beginning of time.
And I don't think it's an unreasonable point to argue, "Let's try to stem the amount of dangerous chemicals smuggled into the country across a national border to perhaps make those chemicals less available to young people and maybe save a few lives.