If they were beating his car, the antifas should have been arrested as well.
In that video, they were beating his car as he was in the middle of ramming them at high speed. They slowed the video down to make it look like he was driving casually, but the little snip they showed there was after he took a running start and was slamming into them at I would guess at least 40 if not faster.
Beating his car while he is ramming into them at high speed could easily be argued as self defense or an attempt to stop murder.