Characters discussing morality

I’ve been playing around with a dark little idea that fills in some backstory detail for the final volume of the Stars Trilogy, which is still far short of its proposed total. The following excerpt is an attempt to throw the light of discourse onto why otherwise cultured and civilised peoples can allow, even rejoice in, terrible things done for their cause. This is a topic which has always fascinated me. See what you think.

“Why did the Gaians insist on using human grown neural cells for their Assault Cyborgs, not artificial neural nets? Why did they have to core out all those millions? Kill all those poor people?”
“Cost. Autonomous neural net manufacturing technology used to be amazingly expensive and glitchy, even as recently as ten years ago. I guess they found it cheaper to just harvest pre grown material for cores. Do the math. A thousand assault units at a hundredth of the cost of a full Biotech AI means you can afford a hundred times as many. Simple. It doesn’t matter that there’s only a twelve percent success rate. To the Gaians that was perfectly acceptable because there were plenty more dissidents where they came from.” Suresh Khan raised a philosophical jet black eyebrow at the newcomer.
“That’s sick. The mere thought makes me want to throw up.”
“Congratulations. That at least proves you’re still human.”
“Considering it was humans that thought it up, that’s not much of a compliment.”
“Not all humans, just a few.”
“That few is too many.”
“You know, it’s amazing how many think that everyone else should think as they do, and given the opportunity would murder millions to make them do so.”
“That’s just cynical rubbish!”
“Look in the mirror and ask yourself the question.”
“Crap!”
“Really? Aren’t you being a little dishonest now?”
“No.”
“The question is this. Given the opportunity to make what you think is the perfect society. Everything exactly what you want it to be, world peace, everyone living in harmony, who would you be willing to kill or have killed?”
“That’s an unfair question! People don’t have to die for a society to become perfect!”
“No it isn’t unfair. It’s actually just about the fairest question there is. There will always be those with a contrary view, and as putative leader, it is your responsibility to manage societies response. Who and how many are you willing to send to your executioners?”
“No-one!”
“Even if they pose a physical threat to your perfect society? Even if they murder and terrorise at will? I’ll ask you again. How will you kill them, and how many are you willing to kill?”
“Well there’s the people who created the Gaian murder machine. Most of them are dead anyway. There’s also the people who gave the orders for Ahmed to be blown out of the sky.”
“And?”
“The people who did the killing and everyone who approved of it.”
“Good answers. Now where would you stop?”
“I don’t know.”
“Now you know why I disapprove of killing.”
“But, but, you’ve killed more Gaian Borg and soldiers than anyone else I know.”
“Did I say I enjoyed it?”
“No, but you’re the one lecturing me on the morality of killing.”
“Have I ever even suggested killing one of our own people?”
“That’s not the same and you know it! What about him? He’s killed more people than anyone in the history of the world.” A quivering finger pointed at Richard, who briefly glanced at the accusing digit before returning to his studying.
“Now you know that this isn’t what this discussion is about. It’s about how many people are you willing to have killed to get what you want?” Suresh sighed and leaned back for a moment, arms folded. “ One death? Ten? A thousand? Ten million?”
“Now you’re being ridiculous.”
“No. It’s a perfectly valid question. How many, and where do you stop?”