More realistically, I think it is rarely this simple, on either side. I'm sure that usually there is a feedback loop of escalating responses.
The premise of the article is Police showing escalating force, increases escalation of protestors.
While likely it's a feedback loop, the police are expected to keep the peace; so there exists a higher standard for their behavior.
Yet, an oft criticism is that LE agencies don't always get the de-escalation training they need.