I don't give a hoot if it was "legal" for him to do. I am sick and tired of hearing a punch can kill you. It did not in this case and the CC'er seemed to not have been injured. So that negates the fact "it cold kill you" it did not. Now, is he afraid of another punch? Well, the first one did not do much.
Look, I am not saying go mano on mano with everybody and we do not know the physical charateristics of each man. But any abled body person that feels the need to take out his gun after getting punched that did not apparently affect him is IMO wrong, legal or not.
That is a terrible threshold or litmus test for taking out a gun which is designed to KILL someone.
I just can not imagine myself ever taking my gun out after getting punched and that punch did not knock me silly. If someone is a normal healthy male then I suggest they get H2H training and/or deescalation training if they choose to carry a gun. This had disaster in the making and becasue it worked out does not mean it was wise.
This brings to home another point for folks that rely on their gun as their first line of defense. What happens if this was in a posted no gun area? What would this gentleman do in the same situation? If he is not thiking about that now (if you are reading this) he needs to sit down and evaluate his defense strategy. Betcha five bucks he would have hit the dude back or deescalted.