Yes, communism was rampant at the Ivy league institutions prior to the Russian revolution, but they were not a fifth column, working for the Russians against the US.
I think that the early draw in Marxism for the pseudo-intellectual elite was the anti-Christian, humanism of communism, the fact that Marxism offered a man-made, political solution to the chaos of the natural world. If the Marxist could regulate the world, they thought that they could prove man’s superiority and that there is no GOD.
Yup, pure Luciferianism, which Marx wrote as directed by the Bund der Gerechten, Sabbateans all. They know it is "the beautiful lie," guaranteed to fail. And we all know what is supposed to happen when all collapses into chaos. See Sanhedrin 98a.
Now we all can't be saints. So, how can you make the world of sinners but through the lure of "equality"?