I've heard stories, which I've never bothered to check for accuracy, about street drugs being cut with things like rat poison. That seems counter intuitive, right? Even drug addicts probably wouldn't buy from someone who had tried to poison them. Hell, even that may not be true. Drug addiction makes people do things that no rational person could ever truly understand.
I can understand wanting to get them off the street. Living there is simply inhumane. But to do so without also trying to help them, seems like a waste to me. And as long as I'm in a mood to spend other people's money, I would only spend it on programs like that if there was a similar amount spent on prevention. Once they become a junkie, there is very little time to pull them back. Yes, just my uneducated opinion. But the waste in human potential that goes with drug addiction makes it worth the spending, imo, to try and prevent it from happening in the first place. Assuming of course, that we can identify the actual cause, and then come up with an actual prevention.