It's not so much that as the fact it's widely recognized that the American initiatives to deal with the problem (not only the drug/criminality, but also in this case the HIV and other diseases transmitted by junkies, not to forget the public health hazard of used syringes all over the place in any neighborhood with drug addicts) have produced some of the poorest results for the highest cost, and your prisons are full of addicts. In many cities, you still have very large numbers of addicts, and high rates of criminality, violence and other problems associated to or deriving from drug usage. That makes for great TV shows, but little else.
Such clinics/distribution centers have had positive results (and some failures) elsewhere. They generally reduce a bit the criminality related to drug usage. They serve as dumping points for used syringes, reduce the risk of transmitted diseases within and without drug user circles beside giving social workers/healthcare personel a better chance to reach a very difficult, very distrustful population and help some of them to get out instead of ending in jail at the tax payer's cost, or dead. They're not an alternative to the law and order approach of targeting the dealers or cracking down crimes committed by drug users, they're a complementary initiative to mitigate and control some of the side effects of the problem in areas stuck with heavy hard drugs problems.
It's one of those things that benefits from being envisioned in terms of results and cost effectiveness (in money, and socially) rather than from a hardline ideological standpoint, and in this case there's plenty of foreign experiences in these matters, positive and negative, to look into.