If you're a cop it does. And they have. And been exonerated.
Really? You found a way to turn a talk about a fight at Denny's to suit your anti-LEO agenda? Will you provide cites to support your comment? I will say this... LEOs and non LEOs, including anyone oc'ing, would have a case of self defense if being slugged in the face by an attacker while they have a gun on them. It's easy to articulate that if you got knocked out with a gun on you, that you would not be able to defend yourself and your attacker could easily take your gun and use lethal force against you given the right circumstances.
If I was not a LEO, I would definitely not step in and intervene in this Denny's situation. There's a lack of knowledge about who is an aggressor, if it's mutual, and seems like this is just a fist fight. Stepping in (using a chair as one posted) would open yourself up to possibly having to physically defend yourself (they might claim you were an attacker). I know people can get killed during a fight, but it's much more common to get a few bumps and bruises. Keep your guns and fists ready for a much more serious life threatening situation.
If I was a LEO and this occurred in my jurisdiction, I would verbally tell them to stop. If they did not stop, I would call for backup and use my oc spray if I had it on me. You better believe I would not jump into a brawl involving multiple people without having some help. Now if I thought someone was getting seriously injured or possible feared they might be killed, then I would intervene alone.
Like mentioned above, this is a case where you could make a citizen's arrest (breach of peace misdemeanor) if you chose to do so.