Somebody help me out here, when a cop is called because of a "suspicious person" AKA a guy with a holstered gun, what is that called?

Now, my thing on this, is the cop has to respond to it. You then have a few choices, one, argue and try to make your point like that guy did in the video. Two, be nice and let the cop do what he is there to do which is to make sure you are legal to carry. Or three, have a nice calm conversation with the cop explaining everything in a calm manner (unlike Mr. Gun Rights Guy) with the cop letting him know that you know your shit. Now, I'm not an expert on this, but I thought in those situations, a cop has the right to check you out? I know what NRA guys say considering that they have taught at my school and I have heard from them while at the NRA center down here. I also know that everyone has their agenda and will tell others to "fight the good fight" if you will about "standing your legal ground" in situation like this. I want to hear from an officer on this board, what they can legally do if someone calls in a suspicious person with a gun? I think that would be helpful.