Reading about these events affects all of us, just as you've related.
My thinking is that teaching and learning about both German and Japanese war crimes may simply be too much for young souls to bear. Even now, when you are older, it's heartbreaking to study this part of our history.
And this doesn't just apply to the history books. Current events can overwhelm our faith in humanity too.
Throughout 2024 rape and starvation have been used as genocidal tools. But how many of us would point to Gaza as the worst case in point, when in reality the racial genocide in Sudan throughout the past year has been worse, yet it remained under-reported and ignored.
Racism? Do Westerners only care about people whose skin is the same color as theirs? Are the people of the Sahel less important than the people of the Holy Land?
Any one of these atrocities (Germany, Japan, Gaza, Sudan) can cut our faith in humanity, collectively they overwhelm us.