I mean.... come on. Extremes don't help. Again, maybe "objective" is more like "justified subjective?" I can sit there and say "ok this piece of noise rock isn't 'good' to me because it's only one track and one sound, compared to Smegma's last album which had multilayered tracks." Of course, what I pick up on as "good" or "bad" is subjective, subject to perception, etc. But you've heard music you aren't feeling, and music you are; and you can give reasons why, even if it's more nebulous stuff like feel or something.
No, you can't say for a fact that Ayler's better than Brotzmann, but you can compare them using a subset of generally accepted criteria mixed with criteria that may not be "generally accepted," whatever that means.