Emet (and Ascians in general) see us no different from cattle. Much like butchering animals to satisfy our need to consume meat, the Ascians simply see us as "fuel" for their ideals.
Spoilers:
I personally lost all sympathy for Emet when he exclaimed we were worthless to him for being unable to contain all the light from the Lightwardens. It was at that point where he shows, quite clearly, that we are no better than a beast to him. Yes, it's understandable why he is doing it, but it is by no means justifiable. He simply looks down on all life because it doesn't meet his ideals. We are not worthy in his eyes to inherit this star, and and such, we are no better than a fly that has to be squished in order to get his way. That in itself is very degrading, and frankly, I have a hard time understanding why some people support that point of view.
If Emet was victorious, we would be the beast he sees us as (by becoming a warden), and the people in the Source would be rounded up like cattle for mass sacrifice. Let's not forget Zodiark demands a constant supply of aether; aether that would likely come from creatures that are "lesser" than Ascians.