If you need to understand Poland's reasoning, you need to read this book. Killing Warsaw.
On September 1st Poland presented A REPORT ON THE LOSSES
SUFFERED BY POLAND AS A RESULT OF GERMAN AGGRESSION AND OCCUPATION DURING WORLD
WAR II, 1939-1945. The Report consists of three volumes: Volume A - A collection of studies; Volume B - Photographic documentary; Volume C - List of atrocity sites. The download will start automatically.