This is the nail on the head:
public health problem
We've criminalized an absurdly large number of the population for something that is, in and of itself, not a criminal act- for those drugs that are more addictive, like heroin, cocaine, methamphetamine, etc, the approach has demonstrably failed. When kids are told that one puff of marijuana will shred their brain and make them into pothead zombies, then it doesn't happen, that absolutely leads to a pervasive distrust of authority when they tell them the same thing about other drugs- as you point out fknauss.
When we consider that white, affluent drug users are at the same percentage of the population as non-white, poor drug users, but are almost never incarcerated for the same "crime", it becomes evident that the "war" is not on drugs, it's on the poor and disadvantaged. It also hamstrings our ability to address the actual problem through effective means, like treatment, not jail.
But I'm preaching to the choir. Gods the legacy of St Ronnie and Tricky Dick still haunt us today.
“Do the best you can until you know better. Then when you know better, do better.”
- Maya Angelou