No doubt it’s a contributing factor, and a good question… Don’t [know] how it could be quantified, other than having added degrees to the boiling point..

In my city the rioting was initiated by a group of coordinated troublemakers.

Along with the things others have mentioned below, I wonder if another aspect feeding into the response is that many of them have still been working through this as essential workers. To be out there showing up every day, helping keep Americans safe from Covid-19, and yet still being treated as animals by the police, I think I'd probably lose my shit, too.

Yes I believe the virus, social distancing loss of jobs and the unknown future does indeed contribute to a sense of helplessness and fury

Yes of course you have to wonder about that. Certainly when people are afraid they often turn to violence, even against things and people which have no connection with the source of the fear. Things like racism , nationalism and all the movements of hate, rise and rise when people are fearful and stressed. But even more you may well find that you are up against the greatest factor in human life, which is even more powerful than fear, or hate, which is simply boredom.

The speed drunk monkey, creates religions, nations, empires, art and architecture, drains the earth of its resources, poisons land and sea, and then destroys all that it has made equally swiftly, mainly just to feed its need for novelty. And to fulfill its need never to sit still. After weeks of lock down ?