Thanks for sharing your personal experience here. Yeah it's pretty crazy how we treat a health issue as a matter of criminality, like we can just make something illegal to fix a problem. It's the same logic as supply-side thinking. Just make the supply illegal and demand will fall, but that's bullshit.
Max security prisons are a great example. Drugs are not allowed there. It's even an area completely surrounded by walls. There is a demand for drugs though and that demand results in supply reaching where it should not be able to. Demand is king.
To reduce supply, demand must be reduced, and the only way to do that is to create the environmental conditions where people decide they don't want something, and would prefer something else.