It's a good question. And I think the answers could be as varied as the people who choose to answer it.
Why do I shoot.
I could talk about the responsibility of self-defense but that's said much better, by more eloquent fellows than I, here and here.
Roberta said it very succinctly when she stated:
Just wanted to be good enough to be able to say NO! to bad guys in a language they could understand.
Others feel that it is enough just to be able to exercise a God given right.
Let's face it, we don't live in a world of rainbow unicorns and care bear hugs. We live in a world where a portion of our race looks on the rest of us as a resource to be exploited. A walking ATM, if you will. A means to the next fix, the next whatever they want without having to work for it.
I'm not going to rant on the ills of our society or the failure of whatever is the current demon. It is what it is and I have to live in it. And that's the crux of the issue. I live in this world and I want to continue to do so. And no one has the right to take that from me.
Why do I shoot? Why do I carry? Because I will not "go gentle into that good night,".