This is definitely part of the answer. Walking through the streets of San Francisco a while ago with my kids I was shocked to see people just lying on the side walk in pools of their own vomit. Also was very protective of my kids walking past people that were obviously on drugs and out of their minds. These people became not so much people but just a threat. It seemed inhumane to just leave them like that. With that said, I would not want the job of dealing with them for what I am sure is a relatively low salary with the reward of seeing most people you help back on drugs the next week.

That's one of the interesting things I noticed about Amsterdam. It is notorious for the availability of cannabis, but it's very clear that you don't consume in public or around the neighborhood. (Modulo a group of teens I saw passing a joint around in the park). The coffeeshops are clearly intended to contain the drug use. Unlike California where you smell weed everywhere.