In the longer clip online you see a couple of unrelated people, man and woman entering the store. They clearly stopped and noticed him being difficult, it would be worth knowing what was being said really in this case. Seems like the guy was verbally attacking the man's wife in front of his family?
I've been in a couple of legal situations when I stood my ground outside of my job as a park ranger were I had some modicum of legal protection. These were guys coming at me in town on instructions from a local boss involved in poaching. A few weeks apart, same plan to get me dead (small chance) or fired by the gang boss. It was expensive and time consuming in legal fees despite the police being sympathetic to me. I get why cops want something more clear and fair but.. I'd have issues with the department on this.
However.. with a gun comes the responsibility to be able to use it... a split second it the difference between going to the work/supermarket and having a car crash as a driver, sometimes several times a day.
We expect people to be competent to use a car.. but not guns so much? And then paper over this deficiency..
Possibly there is a civil counter-suit to play out here.