It seems astonishing that one day one would live in close proximity to members of another group, with one's own group frequently intermarried with that group, with friendly relations, business partnerships, all sorts of intertwinings, and then one day collectively it would be time to murder them, and that would seem like an appropriate action to take. We considered that there must be something more than simple hatred at work, otherwise they would not have been able to co-exist for so long. I hope that there's more than just hatred in fact, at that... and we discussed the probability that it was greed, and not hatred that sparks the violence. It's one thing to resent another group for their very "otherness" and another thing entirely to profit by their death and destruction. People in desparate economic conditions may find the removal of another group from competition for jobs easier to swallow than just ethnic cleansing.
Personally, I think it would be impossible to motivate a group of people to slaughter another group without motivating them with something other than resentment.. .and that greed is certainly one of the most corrosive of human motivations. People will do for greed what they would never consider doing for fun, pleasure, or maybe even revenge.
Then we considered... is this good? Not everyone is a hateful person, in fact, I believe most people aren't - sure, we're all screaming monkeys somewhere in our brain, but I think most people have a core of decency and desire not to do harm that more than outweighs the impulse to violence. So the incident of sheer rage-inspired violence is fairly low. Whereas .. everyone is greedy to some extent or another, and our culture glorifies it to an extent undreamt of in human history. From the caustic teachings of Ayn Rand to the very roots of capitalism comes the notion that personal property is the be-all and end-all of human existence, and that society exists for no other reason than to protect personal property.
So is the likelihood that people are reluctant to commit genocide unless they stand somehow to garner personal gain from the violence reassuring, or terrifying?