The Karl Marx reference is correct, of course—and shows just how weird this topic really is.
Leftists have always been “cafeteria Marxists”—picking up those pieces they like, ignoring pieces they don’t—and then updating them with more modern templates like Gramsci and Marcuse and the deconstruction folks.
The key point imho is that leftist Jews always considered themselves part of the oppressed masses—no matter how much wealth and power they had in the real world.
Never mind the point that “leftist Jew” is nominally an oxymoron, since the left is out to destroy all religion and ethnic identity.
PS. Franklin Foer, the author of this mess, is himself a “leftist Jew” who used to write for The New Republic.