I don't care how human anybody is, killing fellow humans, except to prevent the crime of others (police and military interventions in very specific cases) is not OK. That line cannot be crossed.

That includes death penalty and political revolutions.

I never claimed it was okay. I just said it was human.

Because you have to draw the line somewhere.

Morale/ethics do change over time, but not killing people has been shown throughout history to be the bare minimum for a decent society, and an accepted standard today. We can discuss and expand on adding more species, kingdoms and domains, but humans are not up for discussion.

I would not be fine with that, no, but then, I'm not fine either with killing other apes and other self-reflecting animals ; my standard vs modern society's accepted standard.

However, in that hypothetical case you describe, it might be up for discussion. My point was that by modern standards, killing other humans is not ok, and not up for discussion.