So you are saying that all drug addicts suffer from mental illness? Normal one day... the next day you take too many Oxy pills and you are mentally ill?
You want a real example? Okay, take my mom. Upstanding mature woman, 50+ years married, Master's Degree in education, book author, active church member, involved family, model citizen, of perfectly sound mind. But she has fibromyalgia and chronic pain, and was prescribed oxycontin for relief. Took it as labeled for a long time, but (as common with chronic pain) it started being less effective. To keep her life tolerable, she wasn't getting enough from her current doctor, who although sympathetic to the returning/rising pain levels knew he couldn't give her more. Adding every other non-prescription pain med didn't handle the pain; she'd spend days curled up unable to function effectively. So she "doctor shopped" and found another doc who would write her a supplemental prescription - without knowing she was already getting supplied elsewhere. She didn't realize the path she was on; she thought she was making a logical choice for meeting her very valid needs. My Dad and all our family - including her doctor son-in-law - had no idea what was going on. After the third doctor got involved, insurance figured out what was going on and cut her off, cold turkey. At that point she started complaining to family about the heartless doctors, and we discovered the situation and intervened.
She was literally baby-steps away from being a full-blown pill addict, despite all the positive things in her life. If she was single and didn't have involved family members, my mom would be one of those vagrant addicts you heartlessly throw away.
Choices? Yes, many individual choices. Not one "I think I'll pop an illegal pill today" choice anywhere. Instead, many thoughtful choices made by a mature upstanding lady, who's very near the top of the intelligence pile. But those multiple choices, each apparently logical in isolation, led somewhere very bad when piled on each other.
So how does that fit your world view?
It's my considered opinion that you've got an overly simplistic view, and it's easier for you to believe the victim is the problem. Because then you aren't personally involved in finding a solution, you just get to point fingers.
Instead, how about remembering that each and every one of those folks has a story, and has REASONS for those choices, even if you in your ivory palace can't see them. Maybe it's not fibromyalgia; maybe they were raped repeatedly as a child by an abusive relative, or pick any other real traumatic history, and they're just trying to numb the pain that won't go away any other way. You don't know, and you don't get to judge.
I'm not saying the addicts are right - but you're definitely wrong.
What did it take to fix Mom's situation? People willing to be involved in her painful life, not people like you saying "She screwed up. She deserves to suffer." Yeah, it sucked for us, Mom's family, to go thru the recovery with her. But I take heart knowing she made it through, and it was worth the pain of being involved.