I try to think how we got here. The theory I developed in college (shared by many I’m sure) is one I have yet to beat: Womb Envy. Biology: women are generally smaller and weaker than men. But they’re also much tougher. Put simply, men are strong enough to overpower a woman and propagate. Women are tough enough to have and nurture children, with or without the aid of a man. Oh, and they’ve also got the equipment to do that, to be part of the life cycle, to create and bond in a way no man ever really will. Somewhere a long time ago a bunch of men got together and said, “If all we do is hunt and gather, let’s make hunting and gathering the awesomest achievement, and let’s make childbirth kinda weak and shameful.” (Source linked below)
Regular readers know that we here at OaO espouse a view of our biological and conscious selves that states that we have at the core a brain like any animal, a very intricate and complex stimulus-response machine, but that we also possess a highly evolved ability to post-hoc narrate that stimulus and response; id est you respond to your surroundings and situations in some way and then, some number of microseconds later, you make up a story about why you responded that way. Sometimes that story models the actions of stimulus and response quite well (I decide to go down to the cafeteria and eat french fries because I'm hungry and the guy in the office next door has french fries and they smell yummy...mmm...french fries), and sometimes it really, really doesn't.
Humans, in the words of Neal Stephenson, are stupendous badasses. But an inescapable fact of our evolution from carbon chain to stupendous badass is that we got here by being unimaginable bastards. Nature, red in tooth and claw, did things we probably don't want to hear about in order for our genes to make it to this point. Somewhere along the line a particular strain of genes thought it might try cooperating with other gene pools instead of brutally trying to wipe them out and see how that worked out, and lo and behold it worked out pretty well. But we're still animals, and the cutthroat bastardry that got us here remains in our genes.
Say you're a male of a mammalian species, and you one day realize that the only way that your genes are going to survive is to impregnate a female and make sure that the resulting offspring survives long enough to reproduce. Then you realize that, as far as reproduction is concerned, your role as a male begins and ends at fire-and-forget (God, I love that metaphor). The gears and wheels turn in your animal brain some more and you realize, "holy crap, after she's impregnated she could just go off and take my offspring and I'd never know what happened to it. Or worse, she could go off and get impregnated by somebody else at the same time and I'd end up protecting somebody else's genes. I have almost no control over this process. This simply won't do." And Bam! You've got womb envy. The terror of not having control over the most basic needs of your genes causes the red-in-truth-and-claw part of your brain to kick in--it sees that the female of the species is generally smaller and weaker and can be physically controlled and decides that anything it needs to do to re-assert that control must be done.
When this mammal is also human and is well practiced in post-hoc explanations for its behavior it feels, you know, a little bit awkward about just exerting brutal control over half the members of our species, so we need to come up with a narrative about why that's okay. Sometimes...actually, pretty much all the time...we wind up with religious dogma. We couch our unimaginable bastardry in some story about how it's written in a Very Important Book that someone somewhere said it brings dishonor to our family when a woman has sex with the wrong person, and therefore she must be killed (or when the religion stops working, we couch our bastardry in made up science that purports to prove what the purveyors of that science already take as a given).
I believe and hope that the tide that made individual bastardry a successful evolutionary strategy has long since turned, and that cooperation amongst a widely diverse gene pool is replacing it as the best strategy for long term survival. It's only that these things happen on a much longer time scale than any human will witness that forces us to continue to endure the unimaginable bastardry that we do to each other. And it's the fact that we exist in such an in-between state that we live with such twisted justifications for that bastardry as "Honor Killings."
I wish we'd evolve just a little quicker, though.