Well genius, if you follow the story you'll observe that the MC has no issues peeping on these girls showering or sleeping in the same bed with them in only their underwear, yet when they make flirtatious comments or suggestions he cluthes his pearls. If he was with such high morality in seeing these girls as his true daughters and raising them he'd never look sexually or engage in these types of behavior with them since you want to claim this game is "realistic". The spectrum of his behavior is unbalanced IMO. It makes no sense that he willingly has sex with the girls yet will become offended by them becoming flirty or wearing skimpy clothes.