Hitler and Nazi's were literal pikers compared to the evil and poison of Karl Mark and Engels philosophy. Communism is the worst thing to happen in the history of civilization- Muslim/Islam is a distant second.
It's funny that Marx's philosophies have led to death and destruction everywhere it was allowed to ferment, Lenin, Stalin, and Mao using in part Marx's theories led to the deaths of 100's of millions of people, yet Hitler is Voldermort. And somehow worse than all of them combined. Makes sense.
From a Utilitarian standpoint, that is perfectly logical. Communism has killed 100+ million more people. And it's not finished, apparently.
Another thing you have to remember is that the National Socialist German Worker's Party, AKA the Nazis, was formed as a backlash against communism.
No communism. No Nazis. Hitler probably would have lived out his days as a mediocre painter.