Excellent question. What's the answer, Alan?
The answer is the police
were responsible in many cases of not doing their jobs.
They didn't prevent riots because politicians held them back. They let looters loot, rioters riot, and thieves steal from businesses and burn them down.
The police were told to back off. In one town, rioters occupied an entire geographic area and practically destroyed the police sub-station. Nothing was done for days or weeks. It was like an occupying army.
It was similar with Jan 6th except, in this case, there weren't enough police because the commander refused additional help offered by the military and other outside police units. So a demonstration was allowed to devolve into a riot. Why did the commander refuse the help? Were politicians also involved in holding them back like in the BLM riots?