I think a fundamental problem is that people do not trust the designers or engineering; IME/IMO they have been steered and often misled by marketing to believe in things that either don't exist or do not apply.
No doubt such people exist but I do think this is an extreme strawman argument that is often used to discredit anyone who even says anything about hearing. There are people who don't necessarily say you can't measure things that show the difference, or that measurements are useless and yet believe they can hear certain differences. In the extreme everyone one can hear if the amp is bad enough. So that should not be a controversial view to hold by itself.
There are many amps I have heard that I didn't like the sound of. If you are a musician you hear a lot of crappy amps. So there is no doubt that some amps are just bad sounding and their measurements whatever that is will show why. It may be as obvious as a very high level of distortion. This doesn't invalidate that the person didn't hear a bad sound. I find it difficult to take some people seriously when they don't seem to even allow for that fact questioning whether it was figment of some imagination and blindly bringing up DBT. There is no DBT scenario here. If anyone claims, they haven't heard a bad amp, they have not heard enough amps. Measurements and ears are not in contradiction here.
As you go up the chain, then it gets into a lot greyer area. Some people can hear a bad sound, some people cannot. This is differences in human hearing capabilities but also training. Not different from a piano tuner who can hear a piano and say that is out of tune borne out by later measurement. But many people just can't determine that. So, one has to allow for the fact that some people can be affected by some types of characteristics (good or bad) of amps even if others cannot. Again this may not be in contradiction to measurements to necessarily dismiss those kinds of claims. And yet you find that happening dogmatically.
My point is that you could allow for someone to be able to differentiate two amps by hearing (that not all necessarily can do) and most likely it will be explained by a measurement. If it cannot be established as to what in the existing set of measurements would explain that description of what someone hears, then there are some things one can do as a scientific approach. The first, is to validate, the observation and this is where one would set up a DBT to ensure that the person can reliably hear that as different from another amp that they don't hear the same. But it is not a given because some people failed that in some tests somewhere, that any person would fail the same - that is a dogmatic one like a Boglehead might say about index funds vs active funds. If they pass the test, then clearly we have insufficiency of measurements OR, what we assumed as inaudible characteristic is actually not inaudible. Any scientist to be intellectually honest would have to be open to that and that actually allows for more investigation which causes progress.
But what I see happening here is more of a dogmatic piling on (like Bogleheads in their forums) over-generalizing on what can be or cannot be heard.
Note that nowhere above have I made a claim that there is a difference that cannot be measured or that I can or cannot hear any difference. The above are comments on the process whose validity is independent of whether one claims to hear a difference or not. But I am not sure some people necessarily make that distinction.
None of those strawmen measurement-opposed 'philes used above.
My only gripe is inapplicable use of science to justify a dogma (not referring to anyone in particular). Happens in all fields. The dogma, if not explicit, implicitly doubting anyone that talks about hearing something good or bad as mistaken or one of those "golden ear" fools. Yes, the claim is that unless they prove by a DBT yada, yada, we are not going to believe it. But it masks a dogma. If I heard an amp sound bad (or good) what is the DBT procedure? If you really want to arrive at a scientific result, I have posted the details of a rigorous study above (it was partly tongue-in-cheek but a valid setup). I don't think anyone has actually done something as rigorous either.
I don't think the ATI guy here was claiming to be anywhere near that strawmen audiophile but just mentioning judging devices by hearing seems to set off the knee-jerk reactions and I think it is plain wrong and not at all representative of those claiming to have a science-based approach.
Bogleheads have gone through the same process where finally the dogmatic opinions (index - good, active - bad) overgeneralizing available studies was finally replaced by contexts and conditions under which those aren't necessarily true (when active managers show some skills by opportunistically going out of the style box to generate alpha, for example). This doesn't mean active funds are always good, or that there aren't large numbers of hucksters as fund managers or that index funds aren't a good idea (unless everyone gets into index funds in which case there is no price discovery and market movements are solely determined by money flows in and out which is really bad!).
I have not said anything inconsistent with what the measurement objectivists rightfully believe, but the use of those principles to advance a dogmatic and not wholly justified view is as much of a problem for meaningful investigation as the audiophools denouncing measurements and this is what I heard in your earlier post that I highlighted and followed up on. I agree with that. Not sure others necessarily get the import of that statement.
Enuf from me on this.