Well, explain why they would have a reason to target his car when there’s no bumper sticker or other telling feature to let them know he wasn’t one of them? He wasn’t even wearing a hat to trigger them, nor was his car a cop car to trigger any BLM members.
I’m not explaining anything except that, at present, not enough is known to draw any final conclusions. But some news reports did say that the cops were moving the “alt-right” demonstrators out of the area. And I haven’t read anything so detailed that it specified what was or was not on his car, or what he was or was not wearing.