Of course, we will never completely or permanently eliminate violence from any society; still, it seems clear that we have actually done a worse job than many. The proliferation of personal weapons and the increasing deadliness of those arms has certainly not made us safer. Our interventions in the affairs of other countries since WWII have had little to do with "protecting freedom"; in general, they have had much more to do with maintaining or increasing political domination of a region for private profit.
I do find that an alarming number of violent incidents (especially mass murder outside of war), are performed by those who I would characterize as having a fundamentalist point of view—the particular religion is irrelevant. They justify their actions on the grounds of a religious or political view that both encourages and justifies deadly behavior, whether attacking a black church, burning a clinic, killing a doctor, attacking a gay gathering, blowing oneself up in the middle of a crowd, or flying a plane into a building.
Intolerance is at the heart of most of these inhumane acts; a few are simply the work of some tragically unhappy or disgruntled person whose rage at "the other" has overcome his own self-pity, humiliation, loneliness, and emptiness. The problem with intolerance—whether factions, sects, or other “us vs them” groupings—is that intolerance does not breed tolerance. On the other hand, tolerance, in the long run, may actually confront, confound, and convert intolerance. The problem, of course, is that it can take decades, even centuries, to accomplish. Still, although so many of our compatriots do everything that they can to discourage tolerance and encourage intolerance because of their identification with their "team," this country, despite all its historical flaws and contradictions, really has moved slowly toward wider acceptance of others, from Roger William's "Bloody Tenent of Persecution" in the 1600's to our current battle for women's rights, LGBT rights, immigrant rights, et al.
As to the NRA’s advocacy of gun proliferation and Trump’s cheerleading for violence and discrimination, do I think that “good” civilians armed with AR-type rifles or most other weaponry will make us safer? Not on your life or mine. I feel quite certain, both intuitively and intellectually, that more and deadlier guns will make us much less safe; neither do I consider those who purchase these weapons on the pretense of defending or protecting this country to be heroes by any definition.