The Boy in the Striped Pajamas

I fail to believe that the son of a high ranking officer in the SS would not know that his country was at war, that the 3rd reich hated Jews, have such glaring problems pronouncing words in his own language. I could go on. The story was moving, this I cannot deny.

There is an absolute wealth of good WW2 lit for kids, this is not it. Why was this adapted for film?