Are you under the impression that gangs would no longer exist and no longer have violent turf wars under a "no substance is illegal" situation?
When you're taking about poverty and getting rid of felonies you have to think is the fact the marijuana going to make the members of "Sex, Money, Murder" gang think "By George, I believe we will now have to earn our collective living by nursing the elderly and painting school gymnasium" .... I mean lets get real. Any time that proponents-of-drug legalization-that-also-believe-it-will-end-gang-violence are ready to come back to reality, I will be waiting for them. :)
As far as the other business, yes racist police actions should be universally reviled. But you have to think if unintendee consequences and the world is not one thing or the other.
I agree with you that there are violent criminals that are never caught committing violent crimes but only end up going to prison because they are caught with a kilo of cocaine; I guess you think that is tragedy that person is in jail and now cannot take care of his or her children. The child would probably also be in poverty if his parents were addicted to Krokodil.
I'm not sure "free heroine for everyone" is as much a panacea for the worlds problems as you suggest.