From what i understand, Japan has a culture that puts more emphasis on family and actually forgiving them than others, it's why some shows have absolutely awful parents yet when their kid doesn't want anything to do with them, the kids are portrayed as being wrong.
It's getting better, but i can see older series and this problem being quite apparent, you are just expected to forgive really negligent or abusive parents at the drop of a hat, heck, a while back, i decided to look at Goranger, the very first Sentai show, just because i was curious at the first series behind two massive franchises, and there is an episode about uniting a father that left his wife and daughter behind for decades so he could go to another country, and now he's coming back and is astounded that she doesn't want anything to do with him, and everyone acts like she is a bad daughter.
That was a kid's show from 1975, the lesson clearly being that you are supposed to forgive your father even if he dissapears for decades, leaves your mother to fend for herself, and doesn't come back or pick his daughter even after his wife dies, because then you are a lousy kid, it's a messed up value, but the idea of forgiving family seems to be much stronger in Japan, i think the author really expects readers to sympathize with the MC and think that is right in telling another girl to apologize to her dad.