Culture evolves slowly, often only changing dramatically across generations. Multiple generations in USA (which is a dominantly exported culture globally) have adopted the "drugs"-are-bad idea as a core belief (it's also worth noting that core beliefs tend not to be very nuanced or discerning, as in this case there's very little ability to discern between different types of "drug" substances).
Culture evolution slows further when large institutions (primarily "the state" here) adopt the same beliefs and make them concrete (by being codified in many laws in this case). This particular effect worsens when the core belief is that some thing is bad and can be outlawed/fought because you get droves of self-righteous politicians who want to make a name for themselves piling on against this Bad Thing.
Those processes need to be reversed and unwound to move past the erroneous core belief.
Bad ideas do die, but they almost always survive much longer than they "should" because of a litany of flaws in human nature/culture/information-flow.
Culture evolution slows further when large institutions (primarily "the state" here) adopt the same beliefs and make them concrete (by being codified in many laws in this case). This particular effect worsens when the core belief is that some thing is bad and can be outlawed/fought because you get droves of self-righteous politicians who want to make a name for themselves piling on against this Bad Thing.
Those processes need to be reversed and unwound to move past the erroneous core belief.
Bad ideas do die, but they almost always survive much longer than they "should" because of a litany of flaws in human nature/culture/information-flow.