Maybe it comes down to it being slightly underestimated quite how much Rinny likes the MC? I haven't had the chance to check out the yandere content yet (I'm definitely going to!), and I could be wrong but I personally came to the conclusion that Rinny legitimately loves the MC, and that's why it was also a bit easier for her to come to her decisions. Thus, I was able to forgive her more easily with this in mind, especially with her honestly believing the MC would be happier that way.
Heya! Noticed a typo bug while playing 66.1 andriod version, where if you do wall milking, choose the incubus partners, and the first option, a certain word in the text that follows is repeatedly replaced with the phrase 'Succubus #2, Rinny, Succubus #3'.
That said, I DID choose the Rinny and succubus partners option first, so maybe there's some hang-up?