Ah, the usual half truths.
Just read Mein Kampf and The Communist Manifesto and see for yourself what the two have in common (hint: a s _ m)
Marx was a Jew and a massive anti-Semite. Strange but true.
The burning of his books is a good example of the revolution eating its own children. All of them do.
The nazis started as Marxists and once Jews were singled out as the group responsible for the Germany’s demise, the eugenics followed, in line with the ideas of that period - eugenics was massive then and Hitler read a lot of it.
(Marie Stopes also loved it, in case you support Plant Parenthood…;)
And the idea was born of the Jews corrupting the German nation (back then nations were referred to as ‘race’) both on economic and biological level. We all know what followed.
Whether it’s nazism, fascism or communism really only depends on which class of people you pick as the enemy and what means you choose to get rid of them. The singling out and hatred are the same, whether it’s Hitler, Stalin or Mao.