First, most people are not at all "well-educated about the effects of recreational drug use", including medical professionals who are mostly only versed in the effects of legal drugs... Or are you referring to "legal" drugs here?
Second, there is a whole pharmacopeia of drugs that elicit a wide range of effects, and many of these drugs are not necessarily particularly "harmful" (e.g., the psychedelics). But really, moderation is the key ingredient in mitigating many of the compounding effects of repeated use (like physical dependency, which is a symptom only of certain classes of drugs).
Third, drugs are fun and people like to do them. Alcohol is a potentially debilitating, life-ruining drug, but we advertise it on the television. I would bet that most medical professionals consume alcohol.
Freedom is about assuming risk. Pretty soon we'll have no risk though, if the Plans continue as Planned.