The number of criminals far exceeds the number of police officers. The number of people who have illegal guns exceeds the number of police officers. Hell, the number of car thieves is greater. If the victim hadn't moved to get his ID in the way he did, this would not have happened. He's not without blame in this. The cop's reaction was for self-preservation, but he probably would have survived being shot, assuming a shooter doesn't get a head shot.
I think the cop over-reacted, but it remains to be seen if he had a negative attitude toward Blacks or other minorities before reaching any conclusion. The victim should have stood there and done what he was told, unless the cop completely went off the rails in the exchange (not referring to the shooting, just a "normal" traffic stop. Don't fight, don't argue, don't try to start a major scene. If the ticket is unwarranted (if the guy took his belt off on the street, it WAS warranted, technically), he can fight it in traffic court. It costs time and money, but it's far better than being shot dead.
Other people were at the station- if the cop had cuffed the guy and felt threatened, he should have called for backup before doing anything else but the victim did cause a reaction. He didn't comply- if he had stood there, doing nothing, I doubt this would have happened.