I think you are confusing the shallow tribal identity groups with weak ideological consciousness on the left with the far left; the complex multidimensional nature of diversity and privilege is pretty much the core of intersectionality, which is a pretty key concept for the left, especially (much of) the far left.
Or you're talking about the narrowly economic faction of the far left that sees non-class identity largely as a distraction from class issues, with diversity as a non-issue, and all privilege and discrimination boiling down to class warfare. But even they don't really miss multidimensionality, they just see the multidimensionality as a multipronged distraction.