I agree, but fear of being on the receiving end of violence is at the root of all of it, whether it is from criminals or the government. I wouldn't say the NRA audience is the sole or even primary demographic thinking gun crime is on the rise, but I think fear-mongering rhetoric such as the NRA doles out adds to the general pessimism that goes with hard times. For many people, when things are bad, expectations and perceptions of badness expand to cover more and more aspects of life. We become hyper-aware of the things that stress us, and see them as bigger than they are.
So, while the perceptions of women, PoC and the elderly may vary with the realities in the places they live, their perceptions may also vary with their own relative feelings of vulnerability. The NRA, for its audience, aggressively stokes feelings of vulnerability, too. Just having so many pronouncements of imminent doom blaring from the media all the time can also color the views of non-NRA supporters. I think it all adds to the general national viewpoint.