This is an honest report. Other material I have seen have imputed motive and made assumptions unfairly.
As it happens, I was just down the street from this when it happened by maybe 70 yards. One police car went screaming past and turned the corner to join the other police who were dealing with the individuals you see being knocked down and arrested.
I could smell a strong chemical smell. Some people told me that police maced someone, and maybe that is what I smelled. Or it could have been car exhaust from the police car that went screeching past if the police use some special fuel additive to make it screech past like that.
Unrelated: Today, July 1, there was a nice moment as we happened to be leaving the park where some of the protestors were who had not been intimidated out of attending by state disinformation. This truck pulled out of the parking lot.
Gotta love the sticker on his window.