Your comment suggests you either don't understand my argument or Henderson's idea. What Henderson calls luxury beliefs is specifically irrational beliefs hypocritically adopted by affluent people that trickle down to the lower classes and harms them. Later in my essay, I point out that people belonging to any ingroup can adopt irrational beliefs if it brings them some status within those ingroups, but there is nothing specifically left-wing or elite about this, contrary to how Henderson frames his idea. That's also an easier hypothesis to defend because it's much less specific.

You're also missing the fact that Henderson is reflecting his political bias in how he frames his idea. He likes to promote it as fact and with the veneer of objective neutrality, but he's actually acting as a right-wing propagandist. It's not a coincidence his idea was published in the New York Post, which helped to propagate it more than anywhere else. The bias in his idea is central to my critique.