James Lindsay and his New Disourses project is interesting in its critique of the Left indeed. However, I believe there is a huge mistake which undermines Lindsay's productiveness as a philosopher: he clings to the Leftism as Gnosticism idea (developing some of the Eric Voeglin's insights) while missing the meta-physical side of the questions.
Religions are not just sets of beliefs. They are philosophies, they have metaphysics – each has one of its own (leave aside the fact that the metaphysics of a religion may change under the institutional pressure – see the Catholic church as an example).
Thus, equating the leftism (or any version of Post-Modernism) with Gnosticism is a huge miss.
There is a certain meta-physical background which may be shared by most of the Gnostics and most of the Leftists. But this is an example of the convergent evolution of the ideas.