The protest is about a police murder, so yeah, they are.

There's plenty of bad actors looking drum up violence as well. At the very least you get the kind of person who starts fights in a bar for the sport of it. Police can work with organizers to do something about it or they can choose to let it boil over.

"Let" sounds a bit too passive for a lot of what's happening though.

I guess my point was that at a police brutality protest, you have protestors facing police which is instantly adversarial and a form of counter protest if cards are played poorly. If you have a reopen rally per the example up-thread, you're (very generally speaking) not going to have quite the animosity between them and those securing the area. And combine that with the fact that someone not wanting to rush and reopen is likely to stay at home per state instructions.