fell out quite badly with an American friend over this :-(
They really don't get it, they really think they're surrounded by barbarians about to swoop down on their houses and pillage them.
In my experience they think they're surrounded by criminals who are armed.
And they are probably right.
They want to be able to deter them on a level playing field.
In that sense it's a perfectly logical stance, and it's one of the reasons I would never want to live in the United States.