The letter that you are referring to is really how Ann relates the atrocities to her little world. As a whole the book is a deeply reflective account of her own nature, the nature of the war and finally the nature of humanity. This particular letter gives us a snapshot as to how she copes. We can see Ann maturing from a young girl filled with the fancies of adolescence to a girl deeply troubled about the world crumbling around her, "must I keep thinking about those other people no matter what I am doing?" The answer is yes. Ann continues to think, pray and reflect and hope despite the tragedy that unfolds before her. She tries not to let hate envelope her. These are the most uplifting thing of all.