The Black Lives Matter movement is a movement dedicated to changing the way a black life is currently valued here in America. Currently, the value in a black life is not the same as the life of our white brothers and sisters.
Police brutality is one such way that this fact of life rears its ugly head. A black person (whether they actually committed a crime or were completely innocent) are approached, beaten and, typically, killed. Despite the nature of the encounter being excessive and in disregard to what they're meant to do, they aren't punished in many ways, if any. And the black community once again catches a glimpse of how they're viewed to the majority community.
This, of course, creates a lot of hostility. Fear spreads, accusations are made, communities are divided due to a split in viewpoints. This tends to repeat itself once the next incident rolls around. The constant cycle of bad vibes, naturally, isn't a welcome one. We as people don't want to continuously be exposed to these terrible situations. It takes it's toll on our sanity, and so we'll find something, anything to prove that maybe things aren't as bad as many make it out to be.
That's when pictures or videos of a white cop hugging a black man, or white cops at a predominately black cookout, or cops stopping a black person and handing out ice-cream cones to them crop up. They're lighthearted and are meant to show us that not all cops are bad. They're human. They mess up, have fun, make jokes, play Pokemon Go. They're men and women working to keep society safe the best they can.
Of course, we know this already. That's the issue though. We're not talking about the "good cops" that have fun and play pranks. We're talking about the ones that actually kill people on video. It would seem hard to justify. And yet, it's constantly justified. Those "feel good" moments do nothing to alleviate the fear that comes from seeing people like you being put in situations that are all to similar to each other. Seeing those similar situations occurring with such high frequency causes you to anticipate for when it could be your turn. That's terrifying.
Imagine seeing the all too familiar scene of the cop coming over to the stopped car. You're not sure what the issue is, and your mind is bouncing between the thoughts of "I wonder what the issue is" and "I really hope this isn't another one of those situations." That legitimate fear could run by you a few times, before you're handed an ice-cream cone, but hey, at least you can laugh it off, right?