Not sure if it's a NSFW assertion, but to me the p-zombie experiment seems like the result of a discourse that went off the rails very early and very hard into angels on the head of a pin territory, this lw post notwithstanding.
Like, as far as I can tell, imagining a perfectly cloned reality except with the phenomenon in question assumed away, is supposedly (metaphysical) evidence that the phenomenon exists, except in a separate ontology? Isn't this basically like using reverse Occam's razor to prove that the extra entities are actually necessary, at least as long as they somehow stay mostly in their own universe?
Plus, the implicit assumption that consciousness can be defined as some sort of singular and uniform property you either have or don't seems inherently dodgy and also to be at the core of the contradiction; like, is taking p-zombies too seriously a reaction specifically to a general sense of disappointment that a singular consciousness organelle is nowhere to be found?