These issues are extremely complicated and sadly, mostly related to addiction. For example, cacooper's experience fits the timeline of the opioid crisis almost perfectly. It's not an isolated event.
It's easy to point a finger at perceived ne'er-do-wells and yell shame. It won't fix the problem though. Neither will locking them up (that's also going to cost you a shitload of money), withholding services, or even refusing to visit the areas where they are. Scratch hard enough, and you'll find a junkie very close to home. Not many people want to talk about that though, so the problems are often hidden from view when it can be done.
Uncovering their story requires a little more effort, but if you can stand to take the time and listen without judgement, you'll hear a wide range of heart breaking stories and challenges that are extreme (even before the addiction).
In fact, a number of members of this forum are former and current alcoholics. Who knows how many are addicted to opioids? I'm sure there are some.
There are always some true deadbeats mixed in. Those are the ones most people get joy out of pointing to, but they don't represent the majority, from my experience.
I've personally heard stories about child abuse victims, domestic abuse victims, people who were addicted from prescribed drugs, single bad decisions that turned into a chronic life of misery, and all kinds of other stories. I'm not absolving them of responsibility, but the truth is often more messy than we want to believe.
In fact, not long ago, in my "upper class" neighbourhood in North America, a young teenager overdosed and died from what was supposedly a hidden addiction. It started a commission, but only because he was privileged. He was prescribed opioids for an athletic injury and got hooked. It's not uncommon, and it can happen to anyone. The less money you have, the closer you are to skid row in any downtown where it becomes much more visible -like taking a dump in a store front. Anyone who has wrestled with addiction could tell you a horror story, if you take the time to listen. You might still think they are worthless, but at least you will have some more understanding for what led to it.
The junkies you see in downtown cores (they are also in suburbia as well, but more easily hidden while finances last) are not "addicted" to marijuana.
Let's be honest.
Anyone who has ever smoked a joint knows that you don't end up on the street, shitting in a flower bed because of it. Let alone passing out. Alcohol can easily do that, but marijuana? That's tough to do. That's straight out of movies like Reefer Madness. It's about as addictive as using sage in your cooking.
The reasons why these problems exist very likely (I would say almost entirely) have nothing to do with local policy. The local policies are often a municipality doing the best they can (or think they can) to deal with an enormous problem with roots that are a tangled mess of a system much bigger than their city bounds. Cities are not equipped to deal with these problems. They don't have the money, nor the true power. Easy to blame them, but then if you look behind the curtain and see what their options really are, you'll find no easy solution.
Being a city planner, particularly for a large urban area, is a very difficult job with a lot of moving parts. A horrible job to have, really. I have no skin in the game for any city mentioned in this thread. I just happen to know some city planners, and I can tell you from first hand knowledge that the problems look so simple, until you have to deal with them and find out all of the knock on effects of every decision being made.
Some things look like a complete bonehead move (and maybe they are in cases - I can't comment on any of the examples in this thread because I know nothing about their level of planning), but sometimes, there was also a good reason with some really weird side effects. Looks so simple, but as in almost everything in life, it is never the case.
It just makes great fodder for the armchair critic.
I don't have the answers (no single person or ideology will), but I do recognize the complexity, which is vast. It seems we may be destined for it, as complex systems seem to trend toward chaos. Civilization and governance may not be an exception, as things grow too big for any one city, let alone person, to deal with it all.
Hopefully there is some optimism somewhere. It's a very sad tale.