Humans don’t have to do it. Just like widespread rape in the animal kingdom and in human history doesn’t give me moral justification to do it today.

Though even before getting that far, humans are participants in one of your scenarios and not the other. What other animal behaviors justify your human behaviors? Can any of them? Does another intelligence have moral justification in farming humans on the same basis?

There are some absurd reductios here that you’d have to sign off on.