And why do nations agree to international treaties and conventions, then? It´s illegal to take art from the losing nation. So, it´s very well Germany´s right to get the art back. Germany lost 1/4 of its territory as a “compensation”.
After WWI and WWII, Germany is lucky to exist. I’m not very sympathetic about Germany’s losses.
Nations agree to international treaties because they sound nice, and they think they can manipulate them to their advantage.