In children's publishing it may wrongly reasoned that by viewing the events through the eyes of a witness, it puts distance between the reader and the traumatic events suffered by the victims of crimes like Japanese Interment.
But this is doing a disservice to children who despite their age and the age we live in, are still enduring racism, bigotry, cruelty and hatred. It isn't a thing of the past. And there should be book for them as well. Books where the oppressed endure.
Some excellent books that tell authentic stories about the Japanese Internment are:
Obasan by Joy Kogawa
Torn Apart: The Internment Diary of Mary Kobayashi by Susan Aihoshi
Home of the Brave by Allen Say
A Place Where Sunflowers Grow by Amy Lee-Tai