Presuming you're a reasonable person, that won't be the issue. The issue will revolve around the provocation. You can't provoke a fight without the risk of liability should it escalate to a point where you were in fear of your life. Worse yet, it appears there are incidents in the past of this individual provoking arguments over the parking space, and threatening parkers. And possibility an incident in which he waved a firearm.
I would not provoke an incident like that when armed. I acknowledge that the distance was such that I would consider an angry young man larger than younger than me a threat. And look at the video. After being thrown down but prior to drawing his weapon another young man in a blue tshirt approaches him. Then flees when he sees the weapon. That man in the blue t shirt is a threat as well.
There is a lot of talk about provocation.
The fact of the matter is, all the way from getting the wrong order at a fast food drive-thru, to being asked to be quiet at a movie, we know that certain recognizable people are provoked very easily.
We should have picked our own damn cotton.