As I remember, I questioned his hubris, not his credentials
No, you questioned Luther's credentials when you initially asked:
I argue from logic. Can you tell me where , in the authentic teachings of the Catholic Church any of Luthers accusations were taught? I think people, including Luther think much of what as spoken as opinion by some Catholics were authentic and infallible teachings when they were not.
He disputed the teachings of the church on indulgences and Purgatory - things that were part of the official teachings and actions associated with those teachings. If Luther didn't know "official" teachings, then no one did.