Barry - everything you say is correct on a fixed pitch instrument like a piano or a guitar (although the guitar has some facility to change pitch by bending or applying variable pressure on the frets). But a pedal steel is fundamentally not a fixed pitch instrument. No matter how you do it, tuning is a compromise. That is the only 'fact' here.
It doesn't matter a whit to me how anybody else tunes. I came on here after decades playing guitar, and before that piano - I tuned everything ET using a simple tuner. But after listening to the reasoned arguments of many fine players here, and also doing the math, I decided to
listen to the difference. I ultimately concluded that forcing myself to tune by ear using something closer to JI sounds better for what I'm doing on pedal steel - to me.
But don't tell a beginner he needs a $200 tuner when a $25 tuner will do -- that's really unacceptable, and is the reason why I am trying so forcefully to clear up the confusion here ... Everyone is entitled to an opinion, but factually incorrect "opinions" based on ignorance or misunderstanding that confuse or intimidate beginners, or that cause them to waste their hard-earned money, need to be corrected.
You can't 'forcefully' insist on anything here. The majority of serious professional pedal steel players I've run into tune significantly away from equal temperment, and they're neither ignorant nor tone-deaf. You're using some pretty strong language that is not called for.
BTW - I already and completely agreed with you that one doesn't need a special tuner - when you tune so it 'sounds good', the ears trump. I don't claim to have everything figured out at all, but I guarantee you that I and many others noticed how much better my intonation got when I started using my ears instead of some mathematical formula. Don't get me wrong - I'm fine with mathematical formulae when they fit. I have been teaching science, engineering, math, and logic for a long time, and I honestly don't need a lecture on logical thinking.
ET is, more or less, a minimum RMS (root-mean-squared) error proposition - it's a form of optimization of pitch errors in all positions, assuming that the relative pitch intervals are fixed. But if one wants to favor certain pitch intervals, and these are mainly the ones used, a different optimization may work better. Then there's the fact steel guitars are inherently not fixed-pitch, which also changes the optimization criteria - microtonal shifts and slight bar slants can change this whole equation.
I really think that getting one's pitch discrimination ability together is perhaps the most important part of this instrument. But if someone wants to use a $200 tuner to pre-program offsets so they can tune to their ear standard silently on a stage, I think that is entirely reasonable.