Well put

Speaking of morality, there’s this. The reason so many self-defense people believe it’s okay to shoot an attacker, after you add up the cold equations and come to the inevitable conclusion that someone is about to die, isn’t because we have flexible moral compasses. Nor do we study criminal violence because we secretly feel fascinated by evil. Not at all! The reason we accept using deadly force to defend the innocent is because we believe it’s actively good to save innocent lives, including your own. The reason we study past criminal events and try to understand how they happened is because we want to know how to save the lives of innocent people during future criminal events. The reason we learn the physical skills of self-defense is because we want to protect the lives of people we love. The key for each of these things is in the goal: saving innocent life.

Yes, using a firearm to save an innocent life might result in the death of an attacker. But that’s not our primary choice, and it’s not the goal. When you use a firearm in appropriate circumstances, you face an attacker who has already made the most important decision of all. That person made the decision that someone is going to die or be seriously injured today. Given the time you have and the situation you face, you cannot change that person’s decision or undo it. The choice that death will happen has already been made, and not by you. That means there’s only one choice left for you to make: whether or not you will save the life of an innocent person, a person who would surely die or be permanently maimed if you failed to act.