From what johnhe posted, worth noting that Switzerland, Canada and Israel all have much higher gun ownership and availability than the other countries. So while gun availability certainly allows the Yanks to shoot each other more easily, it doesnt really seem to be the reason they murder each other at such rates…
I carry a handgun, because I live in a country where one day I feel I might need it, and because I can. I also train a lot (few hundred rounds a month minimum), partly because I feel its part of the resposibility of having a gun and I also enjoy the sporting aspect of course. However I am very glad that even here where concealed carry is legal, its prohibitively expensive and extremely difficult to get the permission… Its definitely not something for everyone, or even most people.