What she did is a combo of some very Japanese social values. She asked her dad what she should do to make sure she's useful/valuable to the family and the father said that she shouldn't betray her inner thoughts/emotions to others in order to not show weakness. So she did that. But to such an extent that she wouldn't show her feelings to anyone including them. Even when he realized that he regretted putting her in that position. And she continues to stick to that because she feels obligated to repay her parents for taking her in and raising her even though she's not their actual daughter.
Both that guarding of your inner thoughts and not showing them outwardly and a strong sense of duty/piety to your family in repayment for raising you and providing for you are very important in Japanese culture.
The fact that you don't see them the same way and interpret what's happening negatively isn't a symptom of bad writing. It's an issue of the author writing for a Japanese audience that will automatically understand these things and what happens when the story is exported to people from cultures that view those things in the same way. It's not a problem or anyone's fault. It's just a thing that happens when you cross boundaries where you can no longer take for granted that what the author writes and what the audience reads/interprets are going to be based on the same point of view.
Agreed. I feel like a lot of takes I see where people don't approve of plot or characters treats them as though they should behave under the reader's cultural norms and not Japanese cultural norms and society.
It's makes perfect sense for a dutiful daughter to be even more heightened because she is adopted and kids take everything to heart anyway. To be adopted and have this life where your every need and want is supplied for and wanting to pay that back is only natural. They both got caught in his words. Him noticing the change in her heart but not baring his own to her makes sense.
Also this ehoke exchange, the mom has said nothing, not a word, a question or even anything to her husband, she just cried, in the most polite way possible, but it informs us of her role and how she doesn't have a voice in that space but likely perfectly fulfills her role as the wife of a powerful man. Probably also from an arranged marriage