RubaDub.... the sarcasm is deep with that one!
I think it is simple. In America the sovereign indivual is supposed to be the highest authority in the land.
Other places but a much bigger emphasis on the "collective" good. Those places don't like to see individuals be armed.
Guns takes the authority of the masses and gives it to the individual... wither or not you think that is a god thing depends on your view of the world.