One of my friends who plays in our weekly RPG is a libertarian gun fan. He's a truly sweet guy, very kind, considerate, and mild-mannered. Not "quiet," I don't think he's one of those guys who'll flip out, but he is a male caucasian engineer, so the libertarian is nearly a de facto condition. And after libertarian, believers in a-la-carte social services for those who care to pay for them, the assumption of needing to protect one's self and property seems to extend naturally from there.
I have another friend from high school who was JROTC and then served actively for years. He is also pro-gun and thinks the government should have no ability to restrict what citizens can carry, when and where they're carried, etc. I strongly feel he projects his level of competence and self control out into the other weapon carrying gun fans. We get poor-impulse-control idiots pulling guns on each other in line for pizza or in traffic or wherever. I don't understand how he can be willing to stomach casual, know-nothing fools being able to walk around, preening, with their semiautomatics in Walmart.
In contrast, when I'm in the USA and in a private business that a policeman also happens to be patronizing, I get nervous that the policeman has a gun. Sure, he's trained, yes, he clearly has the right to have that tool at his disposal, but it still makes me nervous that a human is openly carrying a device on his hip for killing other humans. That's the only thing it's made for, and it's here in the donut shop with me, on the hip of a guy who is willing to use it. Why the fuck should that ever, ever not be cause for concern?