Hago never played favourites, he knew that his actions were outside of his control the moment he was told about the prophecy, whatever he did would've led to the same path.
Indra's curse was more than just a spell but something running through his blood, but it was also a necessary evil in order for the shinobi to see the error in their ways. Thanks to the Uchiha shinobi were united and saw their conflict as unnecessary, and thanks to them an Ashura incarnate brought the stability Hagoromo wanted Ashura to bring in the first place.
History repeats itself with or without the Otsutsuki but thanks to the actions of Kaguya's descendants humanity has kept on progressing, Hago gave them chakra, Indra invented ninjutsu, Ashura built a society. The ones that should be blamed should actually be thanked.