[...] even those who talk about "training" the ears would agree that an objective foundation is needed for such training. Otherwise, the whole situation becomes quite murky, as one can be "trained" to prefer highly colored sound.
Therein lies the rub, I think. Colored sound is completely fine when it delights the listener; if eliminating coloration were the goal, no one would listen to tube gear, and I doubt we'd be better off for it.
When it comes to measurements vs subjective listening, I don't believe one excludes the other; both are necessary, in the right balance.
Without measurements, no gear could ever be designed or even repaired. I'm all for measurements, with the caveat that taken too far they can lead to a one-dimensional cultlike nonsense.
Just my 2 cents obviously :)