I disagree with that about the teaching on who started the war. What grade were you teaching?
My wife is Japanese (started as HS penpals...long story). She was well aware and never went to graduate school. She said it was part of her HS history lessons.
And every Japanese person I know has smiled in photos independent of where they were taken.
First time I was in Japan was in 1990, so our timeline for thirty years ago are about the same.
I taught English for kids ranging in age from elementary through high school. I can only relate my own personal experiences and conversations I had with Japanese people living there at that time. I lived there for five years.
Your reporting tracks with mine. My stepdaughter was taught in Japanese school about WW2 including Pearl Harbor and the use of nuclear weapons in Hiroshima and Nagasaki. Maybe it depends on region (she grew up in Fujinomiya)?
She went to “high school” and graduated in Dublin, Ireland and WW2 was definitely taught in that school.