Just look back at the lesson of history. https://youtu.be/YnOF7y-KuHE?t=127
There's no chief-of-a-protest who can take administrative action against some anonymous drunk idiot throwing a brick into a window. There is, however, a chief-of-police who can theoretically do the same about the, ah, bad apples.
Practically, the various chiefs of police seem to be doing everything they can to protect those bad apples from the consequences of their behaviour.
Also, between civilians and police, the police should know better. We give them guns and a mandate to uphold the law, and pay them lots of money to do so. But instead of zero tolerance for criminal behaviour in their ranks, it's all coverups, collusion, the thin blue line, punishing whistleblowers, and lobbying for legislature that grants them them immunity to the consequences.