I read a couple of reports that claim witnesses said a antifa protestor threw a rock into the man's windshield causing him to swerve and gun the car to get away.

Another is reporting that the driver was himself a "anti-Trump counter protestor".

"The time for war has not yet come, but it will come and that soon, and when it does come, my advice is to draw the sword and throw away the scabbard." Gen. T.J. Jackson, March 1861