A good and fair question. I always answer like this: Jews traded their religious fervor for Judaism to their new religion: socialism or liberalism or progressivism. IOW, they had fervor; once they broke with Judaism, the fervor had to find a new home. As we all know, socialism makes its adherents feel very righteous, ‘feel’ being the operative word.
So, while the people who created Marxism were atheists, the background of those who were Jewish would have informed their theories and actions in creating this grand global socialist utopian dream? That is what I was getting at— The notion that Jewish background and connection is relevant to the history of socialism, as opposed to extrapolating from that to a denigration of Jewish people and/or Israel for what the marxists wrought. The vast majority of Jewish people never had any connection to socialist theory or the US communist party, and certainly non-European Jews had no connection whatsoever.