The thing about tasers and pepper spray is that they're both shorter range weapons, the taser a little less so at least. With pepper spray I'd have to get in pretty close for it to be effective, and by then I could be shot dead, and those I were, hypothetically, trying to protect subsequently shot dead.
And one might say that scenario wouldn't have to occur if my opponent didn't have a gun, but gun laws aren't going to stop the wrong person from carrying and using a firearm; people will find a way regardless. And if it's made outright illegal, that'll just make it less regulated. And that's an even scarier thought to me.
I do agree, guns are very dangerous, and they make taking a life far too quick and easy - but - like I said, regardless of legality they exist now in our world, and will be wielded. There are many things we have as a society now in direct response to advancements in technology that wouldn't have been necessary before, that exist solely as a response to those advancements.
As a society, we now have guns. No laws are going to stop that. People are going to use them, and they are going to use them senselessly and needlessly. We know that laws certainly don't stop that.
I know that it isn't ideal. I know that you shouldn't have to take a life, and the very thought pains me; however, guns are an unfortunate fact of life now. It might be necessary to wield a gun, because of the very existence of guns themselves. Violence begetting more violence, but like I mentioned before - the violence someone reasonable uses in a situation could far outweigh what the other person was about to commit.
I see death as a natural part of life, which doesn't necessarily justify killing of course. But, there are times when it happens, and it is better than the alternative.