1. As all the controversy shows, he wasn't "clearly in the wrong". Neither was Eric Gardner, that guy who got choked out, nor all the other cases, the names of whom I started to forget because the reporting became so common place, i.e. it was happening all the time.
2. So let's say a white person and a black person in a car have the same rate of performing a crime (let's say smoking marijuana, a harmless pastime enjoyed by all races). Let's say that if a cop pulls you over while you are smoking marijuana, then you will be arrested. Well if a cop is twice as likely to pull you over if you are black, then there will be twice as many black arrests. This is a simplistic model and doesn't even factor situations where a black person gets pulled over, and definitely gets forced out of his car, handcuffed, and searched, whereas a white person might be able to cordially get away with a smile and a "Yessir".