Prog Rock Man, the elephant in the room is indeed the mind.
But whereas most pro-cablers generally accept there is the possibility that the mind could be affecting their judgment (placebo etc), it's a shame that the anti crowd seem to unquestioningly dismiss the possible negative affects on the mind by formal tests like DBT.
As a skeptic rather than anti-cable person I just have not seen good evidence for the normally extremely small measured differences between "normal cables" being audible and have both measured and blind tested numerous cables myself, of course it would be trivial to make a "cable" audibly different , but to do so you would be making a cable that by an engineering standpoint was fundamentally broken, like the wondrous "light" cables that Stereophile tested a few years ago.
As for DBTs and stress, I personally like DBTs, I find them fun and I pass some and fail others depending on the match between my hearing capabilities as a 52 year old and the magnitude of the differences. As someone with multiple degrees in Psychology (Psychology undergraduate degree, and Occupational Psychology M.Sc inc Psychophysics and Psychometrics) a *little* bit of stress is no big deal, in fact it often increases performance, it is hardly the stress of being on Mastermind or being interviewed for a job and certainly most reports of these formal tests show that "audible-difference-believers" who enter these types of test often do so with extreme confidence in their abilities.
That, I feel, is the real elephant in the room. Or an elephant at least as big as the one you're thinking of.
What really puzzles me is why you keep bringing such topics up so unrelentingly, when it's been done to death so many times before. Just have a rest for a while... it really isn't that important.