A boxing match is a carefully balanced affair. The boxers are matched by weight and record and agree to compete according to a set of rules. There are referees and judges, people who are held accountable for making sure the rules are followed. A mugging or a house break-in is not the same. Only one participant planned and prepared to be there. There is no governing body or agreed upon set of rules, and there certainly are no referees or judges present. Many times when talking to anti-gun folks, I hear the argument " robbery isn't worthy of death" or sometime they say "well, that person could have grabbed a broom or golf club to defend themselves." Deeply ingrained in we Americans is the idea of a fair fight. We feel that response should be "proportionate". Indeed, in Kung Fu (many years ago), I was taught "don't kill if you can maim, don't maim if you can hurt, don't hurt if you can walk away." In a fair fight, that is the right way. Use only enough force to constrain the opponent.
But an unfair fight is a different problem. Most violent criminals are healthy males between 18-30 years old. They arrive at their job, purposed, fit and equipped with the tools of their trade. They prey on the young, the old, the attractive, the small and the weak. (I don't think Chuck Norris has been robbed in a long, long time.) Anti-gunners say if an attacker has a knife, a gun is a disproportionate response. The problem is, even if I pulled a knife too, my abilities are far below my opponent's. If I pull a gun, he has the choice to stop the attack. Most of the time, when faced with a gun, the rational criminal chooses survival and runs, or if he is drunk or drug-crazed, he might decide to press on. At that point, I am faced with using deadly force. Maybe he would only take my wallet, but who can know? If I use deadly force I am reacting to his actions, not his philosophy of crime or a reading of his innermost values. Darn right it is unfair for me to have a gun and him to have a knife or a club. Gun beats knife 9 times out of 10. If his choice is to continue the attack, he might well die. Because I am the good guy, he does not automatically die.