Imagine a mosquito landed on your arm. Would you swat it? Simple socialist logic suggests that you should let it be. After all, all biting mosquitoes are single mothers who need your blood to complete their reproductive cycle. Moreover, the sting isn’t fatal or even disabling to you, merely slightly itchy. Transmission of malaria and West Nile disease is only a factor in some areas, so there’s no long-term threat to your life and health. Let the mosquito be!
Somehow, I get an impression that you would kill that poor, benighted insect that was only following its instincts. So you have no trouble using deadly force to stop a small imposition on you by a being with no moral sense. Fine! Let’s talk about cute, cuddly puppies instead.
Imagine going on a hike and getting surrounded by a pack of canines, wolves or feral dogs. They are obviously hungry and intend to kill and eat you, not necessarily in that order. Like the mosquito, they are driven by necessity. They have no concept of your rights and act quite naturally. Should you give yourself to them generously and nourishingly?
What, you are not keen on being eaten? You really are no friend of nature! And what’s that about a stout stick I am seeing in your hand? Don’t you know that an animal with a broken leg has no chance of survival in the wild!
From the two examples, it follows that you — and most other people — have no trouble using deadly force to rebuff impositions by animals who are only doing what comes naturally to them. A wild animal has no moral sense that it has to ignore in order to prey on you, and so it is as innocent in thought as it is determined to get your flesh and blood.
Now consider an attack by a person. Preying on a member of its own species for food is not natural for humans or apes, as we are not typically cannibals. Attacking to gain material or reproductive advantage is rather more common, but usually not necessary for survival. So a person who attacks you for gain or spite is doing so by choice and not by compulsion. Your life and health are of less concern to him than the expected gain, however minimal. And that disregard comes from a person who should have had at least some exposure to the ethical concept of nonaggression.
Should a person whose immediate survival does not hinge on attacking you and who should know better be given more consideration than the ethically ignorant mosquito and wolf? If so, why? While you are thinking about that, consider also that a person who preys on you won’t change his ways after one attack.
Animals who develop a taste for blood, keep it for a lifetime. Your pain are as much a positive reinforcement for them as the proceeds of brigandage. And worse, the screams of your kids or parents are turn-on as well. It’s conceivable that the spirit of self-sacrifice would lead a person to be a passive victim, though being victimized by a nominal human is no less painful or more romantic than being chewed by by a hyena or a crocodile. Even if you don’t mind death or a lifetime disability from injuries, what of the safety of family and friends? An attacker who kills or maims you will be encourage to do the same to them, while an attacker who gets scared off but not neutralized will just pick easier victims the next time. If a healthy adult proves too dangerous, a human predator will go for a child or an elderly invalid, just as their counterparts in the wild do.
Technical details of self-defense are easy to figure out. The first-world problem we face is making the decision that Human Life is Worth Defending in general, and yours in particular. Other people can’t make that decision for you. You can.