Why not pull a Denmark, legalize and give at no cost heroin to addicts, and get these people back to work? A junkie can be productive, despite an ongoing chemical addiction, whether it be meth, heroin, alcohol or whatever else, many middle class and upper class folks live productive lives despite these addictions.
Why can't we bring these people back into being productive, economically net positive members of society, and deal with their addictions with compassion, as any reasonable human being & the Catholic Church preaches?
I've employed many addicts before, if they have a choice of smashing windows all night to maybe get $100 worth of shit they'll fence for $60, or a gig that'll pay them $110 to pull cabling & set up hardware for 8 hours, they will pick the latter every time. Outside of work hours, don't expect them to be contactable, and watch your shit well, but beyond that this group of humans can be a net positive for our society despite the chemical dependency issues they have.
Tobacco is as addictive as heroin[0], think about how much of a public health issue smoking has been. Do you think it would be that if tobacco was illegal? I could imagine making heroin legal would create many more addicts.
One of the core arguments for marijuana restriction is that it's not nearly as addictive as "hard" drugs. it's comparable to things like alcohol.
Access restriction seems like a good idea when a substance is so addictive that you develop lifelong dependence from it by default.
[0]: http://whyquit.com/whyquit/A_Henningfield_Benowitz.html
According to this, common drugs from least to most addictive (on dependence) are: Marijuana, Caffeine, Alcohol, Cocaine, Heroin, Tobacco