To be honest I would NEVER take a gun into a bar. Really, I have not been to a bar in 6 years. If I were to go to one, it would be to drink and that would mean the firearm stays home. If I were to go and hang out in one as a DD, I would not bring a gun. Like you said, higher prob of a fight or some stupid crud breaking out. Lots of people with diminished capacities for rational thought, OC spray, stun gun (i.e. Less Lethal) protection is good enough for me in such a case.
However, not everyone lives like I do, not everyone has the same habits, and not everyone should have their laws set based on what I do. if you can carry in a bar and follow the laws around alcohol in firearms, then so be it.