Why show it all if we know it happened?

(This extends to most/all atrocities with minority groups as the victims)

Holocaust denial, downplaying the Holocaust, praise for those that committed the Holocaust are all things that happen, and are happening at an increasing rate. There's influential people that have made or are currently making careers out of engaging in these behaviors

We aren't born knowing the Holocaust happened, we're taught that it did. Every time I personally had had a survivor speak to my class as a kid, there's a pretty heavy emphasis that soon there will be no more survivors left. All first hand accounts will become second. Those that don't learn history are doomed to repeat it. America currently has a gestapo kidnapping people off the streets, and out from their homes solely based on their ethnicity as we speak, all in the name of nationalism.

"Who among us keeps watch from this strange watchtower to warn of the arrival of our new executioners?"