Some time ago, on twitter, I read someone had theorized that antifa had infiltrated the police depts and was behind much of these kinds of events.
Which is a nice theory, but this sort of thing was happening 20-30 years ago too - it’s just that the internet, the 24 hour news cycle, and the proliferation of cameras have made this more visible to everyone. All of those are double-edged swords, of course; cameras and creative editing make it more likely that an incident might spark riots, but it also means that a real abuse is more likely to be caught on a bystander’s or victim’s camera and increases the chances that they will be believed and justice will be served.