Exactly. Emet-Selch, who loves talking people's ears off and was trying very hard during Shadowbringers to convince the WoL of the righteousness of his cause would have said something if the plan was to sacrifice a bunch of livestock. Like, "Hydaelyn, in her infinite cruelty, would not even allow us sacrifice the mindless beasts of the star to bring back our bretheren. Does that sound like a righteous goddess to you, playername?" or "Don't worry, after the rejoinings - we will sacrifice some of the plants and animals of the world to bring back our brothers, and once again you will be afforded the protection and guidance we gave the star long ago."