Where did you see the word "Jewish". I didn't see it when I read the text, it's not in the relevant footnote, and I did a search and didn't find it.
Regarding the Marxist part: I'm not an expert on this but I believe it's called "critical theory" https://en.wikipedia.org/wiki/Critical_theory.
What exactly didnt make sense to you with that?
https://en.wikipedia.org/wiki/Frankfurt_School#Cultural_Marx...
"The Southern Poverty Law Center has reported that William S. Lind in 2002 gave a speech to a Holocaust denial conference on the topic of Cultural Marxism. In this speech Lind noted that all the members of The Frankfurt School were "to a man, Jewish", but it is reported that Lind claims not to question whether the Holocaust occurred and suggests he was present in an official capacity for The Free Congress Foundation "to work with a wide variety of groups on an issue-by-issue basis""
Communism promised to be both morally and economically superior to capitalism, but every attempt became morally corrupt and an economic failure. As it became clear that the working class of the liberal democracies wasn’t going to overthrow their “capitalist oppressors,” the Marxist intellectuals transitioned from class warfare to gender and race politics. The core oppressor-oppressed dynamics remained, but now the oppressor is the “white, straight, cis-gendered patriarchy.”
His entire memo is a distillation of reactionary talking points. That overall impression rather than any single argument is probably what pissed off a lot of his coworkers because these battles are much older than him.