So, let me get this right...people with guns in plain view, who you don't know, make you uncomfortable?
I'm afraid that's true for a lot of people.
My wife still remembers being very uncomfortable when she saw a man sitting in a pancake house in Grand Lake, CO with a gun on his hip about four decades ago. It didn't bother me at all--western setting, nice looking group, a Single Six in a fancy western belt rig--but it did bother her.
Why? Conditioning, I think, for one thing. Reflect upon the number of times you have seen a report about a crime on the local news and the corner of the screen was emblazoned with the usual picture of a hand-gun. When I was in school in Chicago years ago, it was always a blue double action revolver; more recently, it was a Smith or Beretta DA semi-auto; and now a Glock-like facsimile, and to me they are all ugly and mean looking. The implication was "gun=crime", and serious tones accompanying the phrases "semi-automatic pistol" and "nine millimeter handgun" added emphasis. Repeat it often enough--gun=crime--and you have classic, Pavlovian conditioning.
Of course I don't know, but I tend to doubt that that's a strong influence with Uncle Billy. Not to ascribe my reactions to him, but when I see a couple of people wearing guns (and we don't, in the populous counties around here, because open carry is not permitted), I look at their countenances and their gaits, and more often that not, it they do not appear very friendly. One's first reaction may just be "why is this fellow doing this, and what is he trying to prove?". Some people just do not seem to realize that they are our ambassadors.
Change a few things--a smile, a nice family with him, his putting some feed or a chainsaw into a pick-up with a happy retriever on the bed, and all of that goes away, for me at least.
The point is well taken that a man wearing a gun openly in a belt holster is probably the least likely person around to start trouble, but the issue is one of perception.
For two people I've talked to in the last three days--an elderly woman at a dinner who believes that legalized CCW will cause things to "be like the wild west" notwithstanding the fact that we've had it for years, and a female clerk at a bird food store who shuddered visibly and with emotion while saying "I hate all guns" (someone had talked about using a BB gun on rats)--that perception is reality.