It may be because of the reports that his car was being attacked, and he may have reacted out of fear. The armchair sleuth brigade took action within minutes to dig down into what really happened there.
Just as the armchair sleuth brigade has stopped the media narrative in its tracks by hitting the social media with all kinds of background information about the "Unite the Right" and the Antifa, it looks like they have also prevented the media from painting the driver of that car as a cartoon villain.
It certainly looks like there is a good chance he was speeding to get away and ran into a car. Why would a terrorist not take out the sidewalk of people and rear end a parked car?