Don't know current Amsterdam situation, but we have a shooting place in Geneva, Switzerland and it works. I mean really works. Streets are cleaner, drug crime is lower. Its not a magical solution to every single problem out there obviously.

I think many people have issue accepting that drug addicts are part of society. Criminalize them, and the whole underworld evolves but it won't affect their numbers much. Put death sentence on drug use, and there will still be healthy population of addicts.

So with your 'drawing line' approach and misleaded comparison to sex trade, you just give ammo fodder for far right-wing populist politics, polarizing society and law enforcement, increasing crime and making it more organized, while achieving very little positive impact. Something like famous US screw-up called War on drugs.