I think you have the order reversed. In principle, we have the absolute right to self-defense regardless of what may be written on a piece of paper. In other words, the 2nd merely codifies an existing right. Since the 2nd helps ensure that individuals are supreme, all other organizations (such as government), are subsidiary to this order.
In order for individuals to associate freely in an open society, we have a wide range of laws in which to regulate behaviour. This includes the principles of private property and threats to bodily harm. Absent any violation of these two elements, our poster is actually running the risk of being arrested himself; a veiled threat is still a threat.
I follow you so far but I thought the BOR was to protect citizens from the government, not each other.
I think it's very debatable whether a threat of any kind was made. I don't think the presence of a pistol implies a threat. Were the situation to be escalated by the loud youths then there is a clear disparity of force and the use of a sidearm is clearly permissible
If it does then what recourse does an armed individual have in dealing with confrontation less that life threatening?
Does being armed mean that one is legally required to endure impoliteness? A guy can't get a Grand Slam plate at Denny's if he's prepared to defend innocent life?
I choose to be much more deferential to rude people when I am armed because I don't relish an escalation of force over simple impoliteness. I drive a lot more politely when armed. I think most armed citizens are the same way.
Given the circumstances that have been described I don't think he did anything wrong.
You're right about the possible intimidation.