They weren't grieving for them, though. It was more of a "oops, their energy returned to the star, no big deal" philosophy. Heck, Hermes was specifically called out repeatedly by Emet precisely for seeing their creations as actually deserving of any concern whatsoever over their fates.You should replay those scenes, too. We are shown, emphatically, that they even possessed funeral rites for their living creations which were killed accidently.