You're right but the sex scene can't be erased(or made in other words) because it's in almost every chapter. Maybe they can't find a uke-like voice that is as erotic or sexy as momo-chan. I think that is SOME reason that it can't be an anime. There are more important reason on why.
SO MANY REASON FOR IT TO NOT TURN INTO AN ANIME 〒_〒(ㄒoㄒ)(╥﹏╥)(╭╮)
Actually, from listening to the drama CD for this manga, Hiro Shimono is an amazing fit for Momo (if none of yall know, same Japanese voice actor for Kokichi Oma from Danganronpa V3 and Dabi from Hero Academia)
It's probably because there's child abuse and rape in the story, so they probably can't do it, or feel that it's too heavy to publish
Im here to say: this one deserves an anime. Why pick Yarichin Bitch Club that doesnt even have a solid plot?? Ghaaad.