> it's hard to argue that decreased genetic diversity will help humans.
Nobody was arguing about what is best for humans.
If the choice of existence for all pigs (randomly selected as an animal commonly used for food) was to live in factory farming conditions or for pigs to go entirely extinct, I'd rather they go extinct. Not for the benefit of humanity, but because never existing is a better outcome for those would-be pigs than living lives full of nothing but suffering.