I don't understand where "justify" came from. It WAS logically consistent. But that's 100% irrelevant. Logic based on faulty assumptions is worthless, this is just "garbage in, garbage out". There is absolutely no morals to be had from garbage assumptions.
> Genocide is always wrong.
I don't think that's correct. Now, it has always been wrong HISTORICALLY, but saying that it is logically impossible to even imagine a science fiction scenario where it's the lesser evil just means you have a lack of imagination.
> but genocide is definitely always wrong, and we can say that he was a morally broken person because of it.
Again I disagree. The immorality of genocide flows downstream from my morals, it's not an axiom. I don't like the long-list-of-axioms family of morality. It doesn't scale, and it can't handle future situations. We need something much more stable than a long list of past mistakes. We need to understand what caused those mistakes, but even more important we need clear and practical rules about how to avoid that entire class of mistakes, including future similar mistakes that we have not made yet.