FWIW, German police regularly used undercover, black-clad, violent agents as a pretext for breaking up peaceful protests. It's probably an established tactic. But the situation in the USA looks very different (from here), violent protesters appear to be a small minority of the problematic people, most of which are just criminals using the opportunity to loot.
There are a lot of bad actors that win with choatic protests.
> "Ich weiß, dass wir bei brisanten Großdemos verdeckt agierende Beamte, die als taktische Provokateure, als vermummte Steinewerfer fungieren, unter die Demonstranten schleusen. Sie werfen auf Befehl Steine oder Flaschen in Richtung der Polizei, damit die dann mit der Räumung beginnen kann.
Translation: "I know that we insert undercover agents as tactical provocateurs, as hooded(disguised) stone throwers, among the protesters during large controversial protests. They throw stones or bottles at our command towards the police so it can begin the evacuation".