My German wife says this is (to a large part) a direct consequence of the fact that the US has a much larger population of people with nothing left to lose. Middle class workers working off a mortgage in suburbia are a lot less likely to become violent killers than underprivileged folk who have precious few career options outside of drug dealing in gangs.
Check out the historical murder rate of Appalachia in the US.
Extremely high gun ownership, extremely low murder rate. I grew up there, deep in poverty, everyone owned guns, and the murder rate was on par with the best of Europe per 100,000 people.
The difference? Cultural. Where I grew up, people simply did not believe in killing each other, period. Desperation was widespread, yet there were no gangs, there were no drive-by shootings.
What you call "people [not believing] in killing each other" is a phenomenon that calls for an explanation. I believe that explanation is simply that there's nothing to be gained from killing a desperately poor person. Appalachia (and other poor rural areas) have no gangs because there's no way to make a profit on organized violence. Gangs and the associated violence happen in cities because that's where some of the people, at least, have money that they can spend on drugs or prostitution or simply be robbed of.
That's an absurd extrapolation. Please try to follow along here! I'll repeat it slowly for you:
Because there's (in general) little to be gained from robbing people in this area, there are no or few violent street gangs and other forms of organized crime like you'd find in various cities where there's a more colorful mix of rich and poor. Lacking an organized criminal element, Appalachia presents not significantly more (nor less) danger to well-off tourists than any other area where poor people live and a few will -by statistics- be criminals; and considerably less than various cities, certainly various neighborhoods, where robbery and other violent crime are common and more or less an "industry."
