The left has never understood postmodernism in any rigorous sense. Derrida and Foucault were derivatives of Nazi Heidegger, simply adding a grab-bag of formulaic deconstruction tactics. This philosophical ethical vacuum suited the Totalitarian moral agenda of the left, who smugly and nihilistically deconstruct traditional discourse and ideology, only to usher in its own through the back door. Social justice warriors are the demon spawn of this ploy, which is ironic as they have no coherent theory of justice.

Postmodernism is an epistemological critique based on math and science (nonlinear dynamics). Nietzsche checked out from the Basel University library over 30 times Cantor's work on set theory (with the diagonalzation proof that the infinity of real numbers exceeds the infinity of rational numbers). Derrida-Foucault minions don't understood Cantor, much less Godel, Turing, Davidson and nonlinear dynamics. So they miss entirely the constructive aspect of postmodernism.