The funny thing about telling someone their whole life that people from Group X hate them and will kill them just for existing is that, even if it's not true, that person generally grows up to hate and fear the members of Group X. Every story that appears to confirm their bias will be taken as irrefutable proof of what monsters the members of Group X are, and every counter-example, even if vastly more numerous, will be disregarded as "the exception that proves the rule" or insufficient to mitigate the bias-confirming examples.
It doesn't matter who Group X is. If you tell a white child that black people are dangerous and that they hate her for her privilege and hold her responsible for slavery, that's the narrative that will frame her worldview. She'll either grow up to be an overt bigot, or she'll be afraid and feel anxiously compelled to please every black person she encounters to prove to them (and to herself) that she's not as bad as she thinks they think she is. She's going to be either hostile or nervous...or possibly both.
Now take that same dynamic, but make the child black and Group X the police. If a black child is immersed in a culture that tells him that the police hate him just for being black and that they'll shoot him if they can find any excuse to do so, he's going to grow up to either have a militant hatred of the police or to be deathly afraid any time he encounters a cop...maybe both.
Cops are trained to observe behavior, both to see cues that someone is about to harm them, and to see cues that a person is being evasive, possibly trying to hide evidence of a crime. So when such a person, whose first concern is staying alive and whose second concern is enforcing the law, encounters someone who a) immediately becomes combative and refuses to cooperate, b) quietly seethes with visible, murderous rage, or c) acts as nervous as someone who has a dead body stuffed full of cocaine stashed in the trunk, how do you think the cop is going to react?
I'll tell you. The threat level goes up, and they respond as they've been trained to when someone acts like that: they regard them as dangerous. So what might have been a smiling encounter and wishing a driver a nice day after warning them about wet roads gets escalated to a situation where orders are being barked and guns get drawn. But because the suspect has been programmed his whole life to believe that the police are doing this out of pure malice, he reacts in exactly the opposite of the way he should. He fights, or runs, or lies, or otherwise does any number of things that are perfectly justifiable to do when you think an all-powerful authority figure is about to murder you, but which are exactly the wrong thing to do when Officer Friendly just wants to see your driver's license.
Blacks get stopped and frisked at a higher rate than whites do because they live in poor, high-crime neighborhoods at higher rates than whites do--neighborhoods that are patrolled much more heavily because there are so many more 911 calls in those areas. And yes, that economic disparity is the result of racism. It's the lingering scar of centuries of economic apartheid. But it has nothing to do with whether or not a cop is a white bigot with a beef against black people. Agencies send units to where the crimes happen.
"Driving-while-black?" Try this experiment: Make a list of ten makes, models, and colors of cars and a random list of license plate numbers. We're going to pretend that this is a list of cars you've been told to be on the lookout for. Could be stolen vehicles, fleeing fugitives, Amber Alerts...it doesn't matter. Your job is to recognize them when you see them. Study this list. Stick it in your pocket. Now walk out onto an overpass that looks over a highway. Without taking out the list, look for any cars that match the ones on it. Also watch for anyone speeding, swerving, changing lanes erratically, following too closely, or anything else that might endanger others. If you can listen to a police scanner, keeping track of what's going on in the rest of the county while you do this, all the better.
A tan Honda Accord goes by. There was one of those on the list! Wasn't there? Take the list out of your pocket and check. Yep! Sure, it's one of the most common cars on the road, but at least you spotted it. Now...what was the plate number? In all likelihood, you couldn't read the plate. Maybe you didn't even see it. If you were in a patrol car, you might try to get close enough to read it and call it in for a check. But unless you're Rain Man, there's no way you read the plate on that car as it whizzed by while you were watching the traffic flow as a whole and focused on picking out makes and models.
But forget the plate. What color was the driver's face? Looking straight down into the windshield from above, you have a much better view than the typical road cop. From the road, mostly what you see when you try to see the driver is a glint of sunlight or street lights, or a dark silhouette. All the silhouettes are dark, even the ones of white people. The only thing you really know about the driver is that there is one.
So how, based on that, could you possibly target people of a particular race? You can't. Of course, this doesn't account for how a cop might treat a driver after she's pulled him over, approached the car, and discovered that he's black. What it does show us is that in most cases, police couldn't possibly pull people over based on the race of the driver even if they wanted to, because they can't tell until the stop has already been made. That inconvenient fact does nothing, however, to slow down the persecution complex of someone who's been raised on the idea that everything in life is rigged against him.
With notable exceptions like Ferguson, police departments openly discriminate in favor of women and minorities. I don't know if it's still the case, but ten years ago, if anybody, of any color, wanted to apply for a job as a cop at the Columbus Division of Police, they had to get the application from a place called the Office of Minority Recruitment. Agencies regularly mandate that their officers attend Cultural Sensitivity training, which is invariably aimed at helping officers learn to understand and sympathize with women and non-whites...regardless of the demographics of the officers attending. Useful as it would be to law enforcement, I've never heard of any agency sponsoring a Cultural Sensitivity training session focusing on understanding Christian fundamentalists or the honor culture of Appalachia or understanding the motivations and psychological makeup of Occupy protesters. When an altercation occurs between a man and a woman, most officers--of either sex--will presume that the male is the aggressor and the female is the victim. Even if the opposite is discovered to be true, they'll typically go easier on her than they would on him. If you don't speak English and you're arrested, police will usually go to some effort to locate a translator to make sure you fully understand your rights. If you speak English and you're just too ignorant to understand the Miranda warning, no special effort will be made to help you understand that confessing and pleading guilty is generally a bad idea.
So most police departments actively root out racism and have been pushing the pendulum in the direction of favoring minorities for over twenty years now, but we still have this persistent urban myth about racist police that's become an article of faith among African-Americans as well as among fearful white people who are eager to prove themselves worthy of black approval. It is this myth that trains young black people to have bad encounters with the police. When you perpetuate the lie that police want to kill black people, when you add your voice to the chorus of voices affirming that this lie is the gospel truth and everybody knows it, you're condemning more black youth to violent deaths and incarceration. It's not the 1950s anymore. The old wounds still hurt and are fresh in the minds of the victims of the racist police departments of ages past. But picking off scabs isn't helping those wounds heal. Passing this PTSD and culture of paranoia onto subsequent generations isn't helping them. If you care about the well-being of black children, give them the opportunity to see the police portrayed the way white children see them. Give them the opportunity to develop a healthy sense of what is and isn't actually dangerous. Quit rigging the game against them. Quit programming them to be victims.