[synicalx]

I suspect it's a result of "blanket" thinking - if we don't punish $illegal_behaviour, then people won't stop doing it. Unfortunately in this case, the punishment is the same as the punishment for just about every other crime and for this particular issue it's less of a punishment and more of a catalyst.

A middle ground would be a good solution IMO - some kind of jail-esque treatment center or set wings in existing jails just for drug users where they undergo some sort of treatment/detox program. I daresay in a lot of cases, voluntary treatment isn't going to work, and I suspect a lot of treatment centers out there now are nowhere near as secure as a jail.