"Why do you believe we are hard wired against doing so? For our own safety, or for our own restraint? I believe accomplishing something as astounding as taking another life should only be as difficult as you make it, wether it's a family member or a stranger."
The human race is hardwired to survive, not as individuals but as a species. The human mind has certain triggers and barriers evolution has set up to help ensure the survival of humans. Whether it be a fear of heights, spiders or clowns they all have primitive survival roots. I'll just name a few for examples
People lacked basic understanding back then, eventually these barriers developed as a fool proof way to avoid these behaviors/things
Fear of Heights - Pretty obvious, was developed because too many people died of falling.
Fear of Spiders - Back in those times, getting bit by one probably meant death. The mind has a lot of triggers towards anything that scuttles in general.
Fear of Clowns - The trade mark white face look clowns give is eerily reminiscent to deathly ill or sick individuals whose skin turns pale.
Claustrophobia - Most likely came from too many pre-homosapiens going into caves or dens where a plethora of life threatening dangers waited.
Behaviors like seeing babies as cute, parental bonds, love, all of it is just for survival. In my opinion(which isn't relevant to this discussion at all) none of this benefits the individual today, it becomes a hindrance.
Really we could just go down a list of behaviors that are enforced by the mind for the survival of the species. Killing one's own is definatley on the list and I imagine it's quite the mental experience. I don't read up much on their testimonies, but as proof don't most serial killers say their first experience was the most memorable? Probably because of the mental reaction to all of it.
One last piece I've struggled with is isolation. Hardwiring tells you to be around people, the reaction to isolation is one of the more violent ones where the mind literally rips itself apart. Clear and cut being away and alone back then meant certain death.
All of this hard-wiring has been proven to exist, just look at the actions of others and you'll realize even though we aren't in those times it still dictates how we live our lives.