Let's presume Nazi Germany did not happen. Young kids would not have references on how damaging extreme nationalism can be therefore the Third Reich could have append anywhere in the world an can happen again if we ignore history.
Atrocity propaganda, mass manipulation by the media and education, the figure of fanatical leaders and their demagogy, the blatant use of psychology and indoctrination for political purposes etc. are known by intellectuals and past wars are used as a warning for those open to it.
Those images of war and destruction may be disturbing but they can also be educational and help a great deal of people develop empathy and give them the will not to make the same mistakes again.
How do wars make societies evolve? Are wars necessary for the evolution of societies? Is humanity doomed to forget and make the same mistakes again because of our animal nature?
I'm looking for authors and reflections on this matter.
"Those who cannot learn from history are doomed to repeat it" Jorge Santayana