2. Stopping is the goal, it’s just that sometimes that means killing... but...
3. Is killing is always wrong? Almost every society and religion has a concept of justified homicide. Sometimes people can act in a way that forfeits their right to walk among us. I don’t accept “guns can kill” is an argument against guns. It’s basically the feature that makes them so desirable for defense. When you have a life or death problem, you are going to call a cop because they will bring a gun. Some of us are skipping that middleman for efficiency.
I’ve made good in my soul that I can take a life if it meant defense of self, family, or other. If you can’t do that, then by all means don’t own a firearm, no one will force you to. We just ask you don’t try and make that decision for us.