Let me play devils advocate a little (or shit starter if you prefer).
Why should we let the idea that addicts will turn to crime stop us from doing the right thing and cutting them off from the public purse. How do we know that many wont just whither away and die (problem solved). Why do those of us who've managed to stay off of drugs, make good decisions about our lives and work hard to make our ends meet have to pay some kind of ransom to keep these losers off our doorstep? Why do we even have to pay to keep them alive? You can cry out about their circumstances but there are plenty of success stories about individuals who've pulled themselves out of the same circumstances and are living productive lives. Let's also think about the fact that many people would probably be willing to donate to non-profit, well-run, efficient charities to help people in these situations if it wasn't for all of the waste of putting that same money through the government programs. Maybe it's my biology background...I just can't see a herd of wildebeests run the way we act. Imagine the herd having to sacrifice some of the healthiest, strongest, fastest individuals to lions so that the frail, weak, sick, old individuals could slow down the herd! Maybe I'm heartless...maybe I've seen the struggles my family made in order to pull themselves up out of poverty...without government checks all along the way. Just hard work and good decision making....even when it was difficult.
[/devil's advocacy]