Just giving the homeless a moldy and bug infested tiny room without any additional help isn't going to help much. It's "housing first", not "housing only".
I don't think you understand addiction and rehab, frankly. Getting people to stop using drugs is quite easy, just keep them away from it for a while. You can send anyone to prison or rehab, and they'll stop using drugs for a while.
The hard part is getting people from restarting to use drugs once you let them free, and you can't even hope to do that successfully unless they are motivated themselves, which they won't be if they live on the street.
Just giving the homeless a moldy and bug infested tiny room without any additional help isn't going to help much. It's "housing first", not "housing only".
I don't think you understand addiction and rehab, frankly. Getting people to stop using drugs is quite easy, just keep them away from it for a while. You can send anyone to prison or rehab, and they'll stop using drugs for a while.
The hard part is getting people from restarting to use drugs once you let them free, and you can't even hope to do that successfully unless they are motivated themselves, which they won't be if they live on the street.