The reason is the character development of Indra is absolutely terrible and Hagaromo is absolutely useless as a father. I mean it starts out strong with Indra and Ashura being close and Indra being close and protective of his little brother. The thing is out of no where as soon as black zetsu almost kills Ashura and Indra unlocks his sharingan he becomes a **** out of nowhere. He all of a sudden becomes closed off from others and harsh whenever he deals with them. There was no great tragedy or reason to be jealous for this to happen it just comes out of nowhere. No explanation is given except I guess awakening the sharingan made him go crazy but I thought it took at least awakening the mangekyou sharingan to cause that. If he should have had anger at anyone it should have been black zetsu who nearly killed his brother but he simply continues to hang out with black zetsu instead. While this is happening Hagaromo simply sits by and does nothing as he watches his son descend into darkness and instead of confronting him about it and trying to help him work through it he simply does nothing. How and I supposed to like that.