Can Somebody Help Me Out Here?

Whenever I blaspheme the sacred name of the Dark Englightenment crap as the post-Christian racialism it is and point out that it is incompatible with Catholic teaching, somebody always denounces me as something called a “Cultural Marxist”. I have no idea what that means but it appears to be the preferred bogeyman of people who go for DE garbage.

Any clues on what the term means? I should at least have some clue what it is if I am to be such a dedicated supporter of it.