I agree with those that said that they didn't have a problem with people bringing a gun when they go to talk to their neighbors. I have a gun pretty much every time I leave the house. Bringing the gun wasn't the problem.
The problem was that he went looking for a fight. If he'd found the people that owned the house, politely asked them if they could try to keep the volume down and then left nobody would have even known that he had a gun.
si vis pacem para bellum