Try to indulge me, as I try to humanize the people you are talking about in a way that might resonate with you.

Imagine you work 40hrs a week, getting paid minimum wage or next to minimum wage, the housing market continues to worsen around you as rent continues to increase but wages don't. If you have a place already and are just barely scraping by living paycheck to paycheck, which a lot of people are these days. One small bad financial day from an emergency or unexpected cost and you're screwed. You miss your rent payment and you get evicted. Now, if you don't have a safety net of people, which we can't guarantee everyone does have living family or friends that will take you in for a month while you get back on your feet, you become homeless. You get fired from work because you've taken too many unpaid days off to try and get your life sorted so you don't have to sleep on the streets. Now you can't get another job because most places won't hire you without an address, and collecting unemployment becomes difficult because if you have no address and no direct deposit you can't get it mailed to you to claim.

As for the drugs that you say they have chosen to ruin their lives with, a pack of cigarettes, a small bag of weed, some opiates, or alcohol costs a whole lot less than rent for a month or even a motel room for the night.

The financial and housing situation for a lot of people out there in the world is really fragile, and if you add on other issues that I didn't list such as mental health issues, lack of education or job experience with any education you have, or existing addiction, it can really add up and make it so your going from sleeping in a small bachelor's apartment one night to sleeping on a park bench the next.

I don't fully ascribe to the concept of communism myself (it's a good label for most folks but I'm too picky about nitty gritty stuff so say I like it when I would want to adjust a few things about it), but I definitely think social housing is how you fix homelessness. Cities and states / provinces waste more money dealing with homelessness the way they do now then just building them socialized housing.