IMO, even those who do keep it in mind don't pay enough mind to WHY it happened and only focus on WHAT happened.
I read "The Nazi Doctors" by Robert Lifton and found it chilling, but it was when I later read "The Road to Serfdom" by F.A. Hayek that I gained a greater understanding of the mindset of the Nazis and how they came to do the things they did.
When the population comes to believe that the people in government have the answer to all the problems, and that the ends justify any means, it always leads to people like Hitler and Stalin leading the likeminded in getting rid of any people they view as threats to their vision of the ideal society.
Hayek's book was the warning of where it leads in relatively vague terms. Lifton's book told specifically where that thinking leads, but I didn't grasp WHY they came to act as they did until Hayek's book laid it out for me.
WE are the ones the far left views as the threat to their vision of the ideal society, and if they aren't stopped, WE'LL be the ones disposed of.
Well said.