It is impossible, in my mind at least, to say "I am on one side on Mike Brown and the other side with Eric Garner", because in both cases the problem is the same: a District Attorney is so scared of pissing off the police union that he chooses not to pursue criminal charges against a police officer, even if he does go through the pantomime of pretending to do so. In both cases (we know in Ferguson, and we can assume in Staten Island), the prosecutor bent over backwards to avoid having the issue go to a full, public, trial, during which the testimony and evidence would be tested at length. By subverting and perverting the grand jury process Bob McCullough also further undermined African Americans' faith in the justice system. The son of a cop who was shot, he refused to recuse himself, but had neither the balls to take a decision not to press for an indictment nor leave the question of guilt or innocence to a jury in a trial. It's almost as if both DAs were scared of what the outcome might be, and intentional or not, the end result is that cops in America have become judge, jury, and executioner. That's not a democracy, that's a police state.
The New York Times has a good piece expanding, in rather more measured terms, the point I was making above: