With respect to all, I disagree with a lot of bajo's posts regarding Argentina but he is 100% right here.
Western society has developed around the process of giving everyone due process. You cannot give due process to everyone but criminals, because that would entail defining someone as a criminal before the process that is supposed to determine that. That means giving legal rights - presumption of innocence, every legally permitted defence, all that - to people who are in fact guilty of crimes.
Everyone can and should complain about the shoddy policing in bad neighborhoods (and often good ones as well) and the societal issues that allow a culture of impunity for criminals, but on a legal level things are very much working as they are supposed to. In all Western societies he justice system is not the same as the police and should never be.
Nobody ever asserted in the 90's that the US government, or for that matter that of New York City or State, was barring entrance to Harlem. It was simply not a very safe place to be. No need for silly hyperbole. And nobody said that you should be killed for being an idiot, rather that being an idiot may very well get you killed. A fine distinction, particularly for idiots, but a real one nonetheless.