I saw this first hand from the locals too in Lisbon. I was up the hill looking over a wall to get a photo of the bay from down a side street. I noticed there was bits of broken bottle cemented into the top Of the wall as a kind of razor wire. When I looked closely and slightly over the wall I found syringes with remnants of brown tar leaking of of them.

Less than the time it took me to realize a window in the house opened and someone was clearly going to give me a good yelling at but when she saw we were just tourists in the alley closed the window mumbling something and left us alone.

So yea, what it does to communities is bad but the solution isn’t to look back at old ways hoping things will change if we try again. As you’ve mentioned, a better solution needs to be found, but it’s a difficult problem, and there aren’t many great ideas going around