I have a much better clue than you do Spook, you just can't see it because you don't want to.
The current policy is what causes the so-called "drug related crimes", not the drugs or the abusers/users. If you allow a market place for drugs to exist, and it's a very lucrative form of revenue, then SOMEONE is going to play the part of the supplier. It ain't gonna be an honest businessman either- it's gonna be criminals. This is what the current policy on drugs, or "War on Drugs", does and has actually created.
You can't get rid of the demand, of course you can jail them all but then you make hardened criminals. It's simply avoiding the problem, the easiest solution is the best right? Not at all.
-SW