Cops respond to reports of man breaking into cars. It's night time. They find a guy in someone's backyard and ask him to halt. He runs and the cops chase him hollering at him to halt. At some point he stops and pulls an object out of his clothing that could be a gun and faces the cops. The cops open fire. It's not a gun, but a cellphone. But it's dark, and the cops can't see clearly what is being pointed at them.
Are the cops guilty of being trigger-happy? Do people know how many times this same scenario is acted out on a daily basis in many American cities? Many, many times. And many times the person being chased instead of a cellphone pulls out a gun and shoots at the cops.
Black males are far more likely to shoot at a cop than non-black males. Cops know this. Which is why when they know they're chasing a black male, they might feel a lot more tense/anxious than when chasing a non-black male.
As far as cops automatically shooting any black male they chase, they just had an incident the other day in Madison, Wis. of cops chasing a black male and tazing him instead of shooting him. That happens a lot as well.
Cops don't automatically shoot black males, but they will respond with deadly force if they think their lives are threatened.
All black males (or any person) has to do to not be shot by a policeman is to surrender when they tell you to and not pull mysterious objects out of your clothing when they command you to put your hands up.