There certainly are right ways to use drugs and doctors are generally supposed to know them. And some people without a medical degree/license happen to know too though they're quite rare to meet. I don't advocate mindless illegal abuse of any substances but I don't advocate mindless falsely-moralist medical purism and all the nonsensical "war on drugs" policy either.

By the way I am about 99% sure that the main reason behind drug abuse epidemics, drug-induced degradation and deaths is lack of relevant education (the real kind, not just the scary "don't use drugs" stuff), lack of understanding and support. NO SUBJECT EVER should be made unspeakable. The more serious a problem is - the harder we are to try to actually understand it and everything relevant to it thoroughly and educate everybody to understand that. Imagine we would just teach kids not to use electricity / not to friend with those who use it and scare them about electrical shocks instead of telling them they should use it with their hands dry.