The Holocaust is a grim setting to base a children’s book in and it would be fair to say that such a book would have its job cut out to get history right. The Boy in the Striped Pyjamas unfortunately doesn’t. The writing is simplistic, the characters are not believable, and its location in time and place isn’t credible.
Is calling it a “historical fable” instead of “historical fiction” enough to justify all of this? My opinion is no.