He is missing a whole lot of the background which helped to cause the Holocaust.
Margaret Sanger (founder of Planned Parenthood) and many prominent "intellectuals", business leaders, and politicians in the early 20th century were promoting ideas of eugenics -- the science of keeping the gene pool pure by eliminating or sterilizing those whom they saw as unfit. It was all the rage in academia and Teddy Roosevelt, Rockefeller, etc., were caught up in the same bandwagon. Some of the ideas they promoted are nothing less than startling to us today.
Eugenics was an accepted notion of the early 20th century and hardly anyone saw anything wrong with it. Germany took it to new levels in the 30's under Hitler when they developed the gas chambers and sterilization programs for those who they thought didn't belong in their society -- homosexuals, mentally ill people, people of limited intelligence, people with certain physical handicaps. Thus when the Jews were demonized more specifically by Hitler it was a natural extension to create more ovens and more ways of exterminating these "unfit" people.
Hitler killed 6 million Jews but he also killed another 4 million Poles and other Eastern Eurpoeans under his own version of eugenics.
Thank God this foundation of aggressively helping nature in assuring the Survival of the Fittest doesn't exist in any developed society anymore, so that precludes a Holocaust like the Hitler version. It still exists in the Middle East, though, in that the Muslims want to exterminate the Jews.
Like breaking the taboo against mass killing by the Bolsheviks who caused death of countless millions of Russians, Ukrainians and others before WWII.
So are you. There was the sordid history of the Spartakusbund in Berlin, converting it into a squalid hell-hole of debauchery, strikes, and rioting.
The question today is not democracy or dictatorship. The question that history has put on the agenda reads: bourgeois democracy or socialist democracy. For the dictatorship of the proletariat does not mean bombs, putsches, coups, riots, and anarchy, as the agents of capitalist profits deliberately and falsely claim. Rather, it means using all instruments of political power to achieve socialism, to expropriate the capitalist class, through and in accordance with the will of the revolutionary majority of the proletariat.
They were communists. Several of their leaders (notably Rosa Luxemburg) were of Jewish ethnicity (as was also true of the Russian revolution). The mass extermination of the middle class after the revolution in Russia and the attempted revolution in Berlin scared the Germans so badly that they fell into Hitler's arms.