I'm not sure what you're saying here. For a start you're conflating drug use, open drug use and drug addiction. Homelessness obviously has some correlation with some types of drug use but there's a lot of non-homeless, non-addicted drug users. And you haven't touched on hard vs soft, addictive vs non-addictive drug use.

I'm not disagreeing because I'm genuinely not sure what point you're making?