Unless we know and understand our past, we are doomed to repeat those failures. Also such was the tidal wave of change that WWII spured on it gave rise to civil rights for minorities, womans rights and technology as we know it today. The world before and after WWII were very, very different places. We have had a period of peace, advancement and democracy unprecedented. Yes it was a horrible period but it allowed us as a species to prioritize who we really want to be.