Stories of police abuse are reasons to crack down on crooked/abusive cops... not to get rid of the police entirely.

Yes, you saw a video of a student injured by a violent cop...

... but violent students assault each other in schools every day - and law enforcement is there to protect them.

This cop was (apparently justifiably) fired. There's no way to fire all of the violent kids. In fact, some of them have only that school as a possible way to avoid a lifetime of violence.

We want to assume that what we see is a representative sample.

What we see is a set of sensationalist videos to make us upset. Nobody records and posts routine cuffs after a fight when one kid's hurt at the hands of another. They don't go viral. So they're not seen and they don't go into the database.

A cop breaks up a fight and hurts a kid, everybody knows.

Had a student a while back who got involved to break up a fight between two girls (call them girl 1 and girl 2). She was homebound, then used a cane for a couple of months, as a result. The girl (1) that did that to her did the same to girl 2. My student managed to delay and spread out the damage enough for the cops to show up. Otherwise, girl 2 would have been in really, really sorry shape.

By the time the cops got there, the first girl had both of the other girls on the ground and was mercilessly kicking them in the gut, the back, the head.

But because it was one kid doing it to another kid with the same skin color, nobody would have cared because it either failed to trigger a trip wire or because the trip wire it triggered would have been inconvenient (and pointing the incident out would be racist or somehow regressive). Had it been a white kid doing it to a black kid or a Latino kid, perhaps it would have been important because it was racist. Had it been a boy doing it to a girl, it would have been sexist. Since it was just brutal, hard core intragroup violence, meh.

Ran into my student a few years after she graduated and was working in a restaurant. She still had a limp.