I recently stopped linking to La Cieca because he wouldn't let me comment any more, something I did on only rare occasions. Yesterday I stopped linking to OC (not Opera Chic--that OC is still probably the best of all the opera blogs) because it trashed Renée Fleming one time too many for me. If Renée says she's now singing better than ever, it's because it's true.
As a cranky old lady, I am as self indulgent as I feel like being, but I try not to trash great artists.
I recall from the days when I was young groups of singers sitting around trashing their betters because they failed some technical ideal or other. This still goes on on YouTube in the comments of practically everyone. Even then I realized that these singers we were trashing were rich and famous, and I was not. It was for me to try to discover what fact of life made this true. In my particular case the discovery was that they had high notes, and I didn't, but never mind.
Your teacher is trying to make your singing conform to some inner ideal. Greatness consists in creating an original identity, one that has never been heard before.