Your proposal is that we open institutions where people can live, eat, sleep, presumably have all of their needs met, and also do as many drugs as they want all day?
There is no way this theoretical free-housing-with-drugs institution would do anything but increase the number of people abusing drugs and decrease the odds of getting them back on their feet.
Can't pay your rent this month? Well if you get addicted to drugs, you get free drugs and free everything at the Free Drugs Institution...
Want to leave the Free Drugs Institution? Oh you don't have any money to get a place of your own and getting a job while you're in the throes of addiction is hard, so you might as well stay at the Free Drugs Institution...
Every single one of these theories relies on the number of drug addicts remaining fixed, but they always ignore the fact that you can't remove all of the costs of doing drugs without dramatically increasing the number of people doing drugs, relapsing, or stuck in addiction cycles.
You presumably aren't the target audience.
There are a lot of people who are working hard to stay clean and keep their addictions at bay because the costs of being addicted are too high: They lose their job, their housing, their ability to support themselves, and their future.
If you offered these people a way to do drugs for free, and a place to stay for free while they did those drugs, the incentives change dramatically.
Drug addicts are also very good at lying to themselves. You'd get people telling themselves they'd only go in "for a couple days" or "for a month or two" who would end up in there for years and years.
I generally think legalization is a good idea. But junkies are always going to be a burden who live on the margins of society and survive by leeching off the rest of us (crime, welfare, donations).
Some guy stoned out of his mind on weed may be harmless, but this is not universally true with all drugs and all people. And your idea lacks an explanation for who will pay for all these free drugs. What's in it for me, as a productive member of society, to finance those drug habits?
What's in it for me as a member of the political mainstream if we allow these dangerous political views that upset our social harmony?