Despite what I'm writing below, I'm not defending Marxism. He was a professor writing about working people...he thought he knew things that were just theories. He wasn't evil though.
That's my point. Marx created communism/Socialism in the same way Hubbard created scientology. I think Marx believed what he wrote and some good (and some very bad) ideas were developed from his writing.
per the Holocaust Encyclopedia,
"Although Karl Marx's own attitude toward Judaism has been characterized as ambivalent at best and hostile at worst, his books were burned in 1933 because of both his Jewish heritage and his socialist ideology. Marx was already named an ideological enemy in Hitler's early writings."
https://en.wikipedia.org/wiki/History_of_antisemitism_in_the_United_States
In a 1938 poll, approximately 60 percent of the respondents held a low opinion of Jews, labeling them "greedy," "dishonest," and "pushy."[29] 41 percent of respondents agreed that Jews had "too much power in the United States," and this figure rose to 58 percent by 1945.[30] Several surveys taken from 1940 to 1946 found that Jews were seen as a greater threat to the welfare of the United States than any other national, religious, or racial group.
So, while yes, some of his writings seem to reflect anti-Semitism, that's like pointing out someone in the 1700's owned a slave, or in the early 20th century believed in Eugenics. Its unfortunate, but expected.
Mussolini - He was Marxist when he thought it would get him power.
Mussolini's writings eventually indicated that he had abandoned Marxism and egalitarianism in favor of Nietzsche's übermensch concept and anti-egalitarianism... After being ousted by the Italian Socialist Party for his support of Italian intervention, Mussolini made a radical transformation, ending his support for class conflict and joining in support of revolutionary nationalism transcending class lines.