High Schools failed to teach compulsory subjects

Hi! This week, I heard a very shocking news which is actually related to myself. On Octiber 31st, it turned out that out of 236 high schools in Tokyo prefecture, 11 high schools didn't teach compulsory subjects, such as world history. Of the 11 high schools, Aoyama Gakuin High School was one of them! In Aoyama Gakuin, all 476 third year students failed to learn health, which they were supposed to and lacking 1 credit for graduation. Instead of including health class, the school included gym class in the second year od high school. When I heard about this, I was very surprised and also shocked because I'm a graduate from Aoyama Gakuin High School. That means, my classmates and I didn't get enough credit, but still graduated from high school. I didn't know that you had to take 2 years of health until now. I think it's not fair that some high schools like Aoyama Gakuin didn't teach what they were supposed to teach. Also, I thought that the Japanese university entrance exam system might be the cause of this problem. Other schools cut classes like world history and ethics because these classes are not imprtant for the preparation of the university entrance exam.