In In The Days Of The Comet, after the change, the narrator's mother tells him that she still believes that there is a Hell. However, she never did believe that anyone went there! He is pleased that she has reached this theological accommodation.
Changes of attitude would solve a lot of problems. Thus, when two young girls swearing blood-sisterhood each grant the other a veto over the other's boyfriends or partners, all that is necessary is that each girl later resolves not to exercise this veto.
Think about the problems that would simply end if every Merseian one day woke up to realize that they could share the galaxy with all other rational species. As it happens, the Merseians eventually fail to conquer the galaxy in any case so they would have been better advised to invest their energies in some other cause. If any deity had been capable of directing the Merseians' evolution and history in such a way that their motivations were less aggressive when they first encountered humanity but that deity had failed to do this, then s/he would have been morally responsible for the emergence of the supremacist ideology of the Roidhunate.