It appears like you are under a misconception, this is an ecchi harem romcom with a revenge side plot. Actually, I'd say that it doesn't even have revenge in it at all, since MC isn't going to do anything to his family.
Man, so many people in comments whining how he did the twins dirty by making them look a bit more feminine. Masculinity doesn't equal attractiveness to women, just look how popular boy bands are. The men there are far from masculine and women still cream themselves over them. Not saying...
i'm assuming he was asking for in universe proof, which she doesn't have by the looks of it. I guess she stayed silent because she was afraid no one would believe her, especially since they were basically fellating their new favorite kakoiiii senpai all the time.