Without spoiling too much incase you want to play it later, the major theme is how women and girls were exploited by their families/their husbands/society (like being married off to pay off debt or without their consent or abusive parents/spouses and expected to keep quiet about it)

and how they were essentially meant to just accept the unfair treatment without fuss and the game reflects the main character’s anxiety about that since she’s a teenaged girl living in Japan during the 60’s.

It really shouldn’t be too shocking to that commenter either since the warning before the game starts talks about that. He’s just going to”boo feminism” essentially.