What are we objectivists missing?

The point of blind testing isn't to claim someone is delusional. All humans have biases, the only way to eliminate bias and continue the investigation into why something sounds different is by testing the claim. 

You mention cables,  if 2 measure "exactly " the same then they will be indistinguishable in an ABX test. The reason people claim they hear differences in components that measure the same is due to confirmation bias. Take sight out of the equation and get back to us with how different they sound.

Subjective claims are null and void for everyone but the one making them. In order to show that the subjective claim has any relevance  beyond that it needs to be verified. This is true for things besides audio as well. I can claim a teapot is orbiting Mars, that I have seen it, but until such time it can be verified this claim is only true for me. This isnt some wild radical notion it's true for all human experiences the idea some ignore it for audio, to claim audio is different is depressing in a way.

100% true. But, this works both ways. For the "objectivists" too

Absolutely. If I say 2 dacs sound the same I will add if it's simply a subjective opinion or one I have tested. 

This thread isn't about cable A sounds better than cable B to John Doe but why will some claim A is sounds different  than B yet measure the same. Are there unknown measurements we need to make? My point is bias has to be eliminated to see if the reason is bias or some unknown before we can begin to investigate this unknown as a real factor.  Share whatever impressions you want but if someone is asking for RELEVANT feedback on a component my or anyones subjective opinion isn't really worth squat.

1 - People are free to share their impressions on anything audio in an audio forum

2 - You pick what is relevant to you. Ignore the rest

3 - Something that may not be relevant to you may be relevant to others

I’ll break it down for you.

I don’t care what you and John Doe discuss about subjective impressions. I do ignore it.

I am free to discuss my impressions on anything audio as well.

If the questions asked in an OP are given subjective impressions as answers then I’ll point out to him or her that’s all they are and should be taken with a grain of salt. 

To return to the OPs question. We can't identify if something else needs to be measured based on subjective listening claims. Bias has to be eliminated first.

None of them most of the time learn with their EARS acoustic concrete science in listening experiments...

Good experiments use trained and untrained listeners. I agree with  a lot of what you say about audio, not all. To me 90% of what we experience is room/ speaker interaction and how we've tuned them with either passive room threats, EQ or both. As long as your electronic system is competently designed and most is, not specifically made to have a sound signature it's  no more than 10% of it, and yes, that's only my opinion.

Perhaps we’re coming from different perspectives. To me subjective and objective could be described thus;

Subjective observation is centered on a person’s own mind and perspectives, as opposed to being general, universal, or scientific. In this way, describing an observation as subjective often implies that it comes with (or is based on) personal biases.

Objective;

Objective most commonly means not influenced by an individual’s personal viewpoint—unbiased (or at least attempting to be unbiased). It’s often used to describe things like observations, decisions, or reports that are based on an unbiased analysis.

Let’s say you’re a restaurant critic. There may be certain foods that you subjectively dislike—ones that are just not to your taste. But when critiquing dishes, you must leave your subjective tastes aside and be objective about what you eat—making objective judgments about things like how it’s cooked and seasoned and how the ingredients work together. Even if you’re served a dish that you subjectively don’t like, it’s your job to objectively assess its quality.

In a scientific experiment, your hypothesis might be based—at least in part—on your subjective opinion about what the results will be. But science is about being completely objective by gathering data and making conclusions based on the data.

In everyday life, your objective opinion is the one that sets aside your subjective preferences or feelings about something and instead assesses it based on facts and reality.

Dictionary dot com

Personally I dislike tube amps, inefficient, to much trouble to maintain, but there are tube amps that are well made, do a competent job within their specs and if someone likes them it’s none of my business. I've heard tube amp I couldn't tell from Solid state it's just my personal bias. Different strokes for different folks. If they start claiming they are superior to Solid State and sound better then I need more than their subjective opinion. How are they superior and have you compared tube amps to solid state in a blind listening test and pick tube amps better than chance.

Well, your question didn't make sense. 

My take is that if you can hear a difference, there must be some difference.  

Not necessarily, depends if bias has been accounted for. 

So what are your opinions on what those differences might be and what are we NOT measuring that would define those differences?

We can measure the audible spectrum for humans. We can even measure the spectrum for dogs and dolphins so I have no idea what your asking for. 

I’m not confusing anything. I seems most of you can’t "comprehend" the fact that everything a human can hear can be measured. How well you hear or how good your listening skills has nothing to do with it. If it’s within the frequency spectrum of human hearing or even dog hearing then we can measure it. 12 year old's can hear way better than anyone on here and everything they hear can be measured. 

I didn't see anything about good music or good sound in the OP. Those are subjective preferences, hearing ability isn't. Young females between the ages of 10 and 14 have the most acute hearing ability.