The events of WW2 (and the story told about it) have become the foundational myth upon which the modern world was built. It is like wondering why the life of Jesus is relevant to Christians two millenia later. The values by which we judge society, who we currently deem good guys and bad guys, how the political and financial industries are run - all of this had a huge turning point because of WW2. The stability of these things today balances precariously on the propaganda about that time.