I dont know...
We can only talk of Human Rights when is the State in the middle (commission or omission).
So, in the dictatorship they tortured and killed people from the State. Thats commission. But when we talk about omission it has to be proven laziness, and by this I mean a systematic omission and proven, that the State did nothing on purpose, or whatever it did it wasnt enough, and from the State taking it as a whole. So if there exists an anti drug office in the police, you cant say that is Human Right violation. You can discuss, yes, if the money they spend there is appropiate, if they do not catch any drug dealer, if they let some big fishes pass, and all that stuff, but honestly I dont think that happens with intention and I dont think they not care. Obviously exist people from the government that is in the bussiness and they take advantage of the place they are in, but also obviously is that there is a huge part of police, intelligence service, etc, that are clearly against drugs and they chase these guys and they catch some of them. The police exists, the law exists and people are very careful when they buy or sell drugs, so thats an indicator that in some level is still working.
Also, the problem is that when you sell drugs theres one who is buying it, and not forced on, hes buying it voluntarily. And when two people want to evade the law, they get toghether anywhere and theres pretty much nothing to do. Police cant enter very easily to every private apartment to arrest people, is not that easy. Today theres a huge market, a lot of people that use different drugs. what you re asking the state to do? chase everyone? thats impossible.
So thats the other face of the problem, the same problem of prostitution, sin clientes no hay trata.