Bottom line: why Americans like their guns. (seriously)
I'd like to point out to our British conversational partners that the reason almost everyone in America owns a gun can be broken down this way:
1: Most suburban and rural areas border large forests full of wild animals, which sometimes go nuts and try to eat things they shouldn't (like children, because they're smaller and less intimidating, apparently). In New Jersey, black bears have been a problem lately, and there have been a few fatalities. When raccoons go rabid here in New York, they usually have to be killed because they'll chase and attack people, giving them rabies. Then there are wild dogs, coyotes (which have been known to attack children, dogs, cats), etc. My sister has had a large bear approach her kitchen door several times this year. SO FAR, it's left her alone; her neighbor has kindly offered to turn it into a rug if it gets too bold. He can do that because he's a gun owner.
I know you brits don't have bears and rabid raccoons wandering around outside, so I'll cut you some slack here. I know the concept of "big furry thing that might try to bite giant chunks out of me" is kind of alien to you. Most of you live in urban areas, right? Or, at most, suburban. And the biggest animal you're likely to see is a neighbor's cat...
A couple of years ago, out in California, a Japanese man was barbecuing in his back yard with his dog, a Shitzu. A large mountain lion leapt over his six foot garden wall, broke the dog's neck, picked it up by the neck, and dragged it back over the wall, all in the space of 10 seconds. The man was astonished. Apparently, in Japan, there are no large, furry things that can eat you. Just like you British guys... It's out of your experience.
We Americans that live close enough to capital-N "Nature" tend to be very protective over our right to own big guns. We have good reason to be.
2: Even if you don't live close enough to the woods to have a bear shuffling around your back yard, you still have to worry about OTHER PEOPLE. People get pissed off at each other all the time. Maybe you're dating someone with an ex that just can't let go. Maybe you have a dispute with someone. Maybe a criminal just decides to rob your house. Whatever.
We Americans find it very comforting that if someone were to try to break into our house and attack or harm us, we could respond by blowing the crap out of that person. We don't have to wait for the cops to show up, IF they show up... Blowing giant holes in an intruder often makes him decide to stop intruding. You'd be surprised what a motivator it is.
And you know, it's not that we're AFRAID of anything... Honestly, it's pretty funny that you british guys, who have the biggest nanny-state in the WORLD, think that way. We're not afraid of anything at all. If something threatens us, we kill it, plain and simple.
Fear is for the unarmed.