You completely missed the point. All of Aya's rant wasn't that Tsubasa's lack of sexual education is normal or not. Everything until chapter 28 page 4 could be treated as your typical "gyaru friendship", where at the end she'd sit beside Tsubasa and tell here "everything is fine, just move on and live happy life". But when Tsubasa tried to make herself the victim here with her "me, myself and I" mindset. That's what broke Aya and she even said her that "it has nothing to do with that". Aya explained Tsubasa why she's bad guy here, but even then, instead of trying to comprehend those words, Tsubasa fortify herself and trying to attack others, which only shows, that she doesn't undestand damn thing. Later, even tho Aya is somehow talking about people in situation similar to Kaede and herself in general, Tsubasa AGAIN put herself first, as if she's the victim - she even says that "I'M suffering now". For a damn second Tsubasa cannot think about others here, only about herself, how badly hurt and sad SHE is. That's what pissed Aya and that's what this rant is all about. Not blaming Tsubasa that she was risen that way or another.