For your last statement, I agree, "active predators" should be restricted or punished because their intent is to cause harm at the cost of others for profit. but if they're just selling the "drug", why should that be restricted? You can force them to inform their customers of the harm,but that's about it.
This is the entire gambling industry! Do you think they don't know that their best customers are addicts who are blowing their kids' college fund?