In addition to what Muss Muggins points out, I saw that there was reference in the article to a lack of apparent hesitation by the cops. That's right. Hesitation is fatal, as shown by decades of study of violent incidents, including dead cops. The time periods for decision and action are measures in hundredths of seconds.
Sadly, the decedent seems to have been a fundamentally decent person, and in my professional experience, they are the hardest to convince not to make unwise decisions. They "know" that they are a good guy and not a problem to cops and others. Cops can't afford to take that at face value. Sometimes people get offended; sometimes they get hurt or killed. Note also that the time frame is consistent with having consumed some amount of alcohol; the amount it takes to have a negative impact on judgment is far less than most people understand. 95% of the human population show impaired judgment and motor skills at .05%; judgment goes first, so figure MAYBE .03% (which for 230 pound Doug is one drink, certainly no more than two).
Note also that his pistol fell out of his holster. There is a hard lesson there - substandard gear is as bad as a substandard gun. I have seen some really unfortunate choices in belts and holsters, both in person and described by writers (including here). This is serious stuff, and if you don't treat it as such, the consequences can be serious.
Then there is the fun and games at stupid places (and a sports bar at almost any time is a stupid place ... late night/early AM when people have been drinking, even if you haven't, it certainly is). Don't go to them. If you think I am wrong, go re-read the article again, and pay someone to apply slap therapy and pull your head out of your seat until you un(screw) yourself. For the love of all that is holy, don't intervene unless you UTTERLY sure of who is who, and what is what, and that an innocent party will be killed or injured if you don't. Myself - I have only come close when cops were engaged in something and needed backup RFN, and I still started with a 911 call.
All of this was preventable, and all of it was the result of utterly ignorant choices by a man who by all indications meant well. Each bad choice led to a subsequent bad choice, just like running down a gravel covered hill.