Devil's advocate: maybe because the author perceives "tickle down economics" as a position adopted by many of the working class and may even aide in survival.
Sorry I was being oblique to signal some snark. You're sort of hitting my point directly: "luxury beliefs" are just whatever you personally believe to be (a) wrongly held and (b) limited to only the aristocracy (ie. not the opinion of "real Americans"). But concretely demonstrating both is kind of difficult and largely relies on your own subjective experience. It's a political cudgel, not a proper tool of inquiry.