In practice this is something we simply do not have enough data points on (places where the population is armed). It’s easy to speculate one way or another, but you are only legally protected in self defense, not homicide. I’m not convinced that people being armed would increase homicide rate, could just as easily decrease it (ie Cold War effect).
As the original comment poster mentioned cars are lethal weapons as well, and you don’t see many intentional hit and runs. Guns are very loud and you’re not likely to go unnoticed committing gun violence.
Personally I don’t know that it is a good thing to have everybody armed, but it really is on nobody but yourself to protect yourself and your dependents. To this end, I carry (and recommend others carry) pepper spray, which is very effective in non-lethally disabling an agitator in self defense without the mental or legal burdens and pains of injuring or killing another human being.
(Disclosure: I used to work in EMS, violence is everywhere in different forms. Additionally I own a shotgun for the sole purpose of hunting food, and I think the idea of “keeping it handy for self defense” is the dumbest home protection idea I’ve ever heard; you’re more likely inflict accidental self harm keeping a weapon handy in the house or carrying it than safely locked up)