The man arrested could probably have said "I'm sorry you feel your fellow citizens should be shot, for expressing their political opinions." Or something to that effect, then got in his car and drove away. Avoidance, is always our first line of defense.
If the veteran was truly a threat to the man arrested and he'd pulled his CCW, then told him to get away, or he'd shoot. Then called the police and reported the disturbance after the man left, or even shot him had he advanced, Williams probably wouldn't have been arrested. As others have said in this thread, we don't know what the witness statements are and we haven't read the officers reports. So we have to wait till all the facts are in.
Speaking of the arresting officers, they were the ones on the ground. They were the ones that heard both sides and arrested Chris Williams. Assuming they are fair men, who follow the law, that tells us a lot right there. Not taking sides, not pre-judging, just noting one of the most salient facts.
"No free man shall ever be debarred the use of arms."- Thomas Jefferson