I loathe the fact that I'm about to bring up political theory for the second time in one calendar year but it's not my fault that modern conservatives hold such deeply illogical beliefs that we have to go back to square goddamn one with these people to try to make sense of them.
In an introductory course on American Government one does not linger on theory. Basically (with one, maybe two class periods available to talk about the basic concepts in politics, the Constitution, and the founding period before moving on to the dozen other topics we have to cover in a semester) most of us hit Locke, Hobbes, Paine, and the rest of the "This is why people choose to govern themselves and to be governed" stuff. There is no heavy lifting. With the time pressure involved, most of us are satisfied if the students grasp the idea of the Social Contract, collective action problems, and the freedom vs. security relationship. I linger on the last two. They are important, so if the students walk away with nothing else I want them to get that.
I explain freedom and security as two opposing ends with a slider on the scale inbetween. We could achieve perfect security, for example, only by giving up all freedom; if everyone were chained in a small box and fed through a tube then nobody could commit crimes against their neighbors. On the other end of the spectrum we achieve perfect freedom in pure anarchy by giving up any semblance of security. Everyone can do anything and you have to sleep sometime. Life is elemental and sad because no meaningful economic or cooperative activity can take place. So in practice every society sets its preferences at some point between the two, accepting that by giving ourselves freedoms we are forfeiting the idea of complete safety. By giving Americans the freedom to move about as they please and buy whatever they can afford (including some things that could be used to do harm) we are choosing (reasonably) to live with some risk. We're never completely safe. As I tell the students, the only way to guarantee that you won't be stabbed on the way to your next class is to create a society in which either cutlery or the right to walk around outside are forbidden. It's certainly not likely to happen, and that's why we choose to live with the minuscule risk that it will.
This is all incredibly simple, yet here I am explaining it because half of adult Americans do not appear to understand it. At one moment we appear to believe that we can protect ourselves from a nebulous and ephemeral threat and at the next moment we are willing to increase vastly the risks to ourselves and to society. The same people, for example, who oppose admitting Syrian refugees because doing so might pose the slightest increase in risk of danger from terrorism are most vocally in favor of letting everyone carry any kind of gun anywhere and at all times. We're so concerned about our security that we are willing to let Syrian refugees die (literally) to protect ourselves, yet we don't see a problem with handing out powerful, high-capacity firearms to any possibly unstable, possibly deranged white guy who can pass a laughable background check (or use one of the many loopholes in gun sales to circumvent even that) and hand over the purchase price. Our national principles can be jettisoned when we're confronted with scary brown refugees but when we deal with the desire some of us have to avoid being murdered at work or school our freedoms are sacrosanct.
The only way to turn that mental detritus into something consistent is to realize that these people accept the risk of being around armed-to-the-teeth dumbasses inasmuch as they assume that the arming will be limited to people like themselves and the violence they meet out will be limited to the dark, scary Other. They certainly aren't envisioning groups of black male teenagers or Mexican immigrants or guys named Hassan walking around open-carrying .223 rifles. They're envisioning themselves and other rednecks enjoying the freedom of being armed and serving as self-contained judge-jury-executioner units. Similarly, they are fine with immigrants who look or act sufficiently like themselves but crap the bed at the mere thought of anyone dressed differently, non-Christian, with a Foreign Name, or, God forbid, dark skinned.
In short, you're unlikely to see the massive proliferation of guns throughout our society as a threat to your security if you picture yourself and people like you, with whom you share an understanding of who is and is not a Threat, as the ones doing all the shooting. In that light it makes perfect sense.