That's exactly why it's so good
. No need for an age changer because the girl is not acting like a 1000 years old wise short elve but actually has a believable behavior for how old we're supposed to imagine her to be, and that is enough (and unfortunately way too rare). Although we need to take in consideration that she is liking it and even making it way too easier for him to corrupt her so comparing to other things we can do in this game, it's really not the "worst". In my opinion, what he does to Alice (and Hina) is "more bad" than what he does to Hayley, because Hayley is not even trying to resist it compared to her mom. She's even having fun somehow.
Also, normally I would agree that everything in VNs should be optional but in this case it seems that the corruption of the family is the main core of the story, so passing up on that would be kinda ridiculous and not worth playing the game at all.
