"In every other form of music,people are appraised on how they perform"

Complete bolleaux (if, as it seems, it implies "solely on how they perform"). In every other form of music (and how do you know it is a form or an "other form" unless there is a defintion, a history, and an analysis?) there are music degrees (for example B. Mus) that depend in a large part on theory and only in a lesser part upon performance skills.

What we have here is an inverted snobbery that values ignorance because it is ignorance. In general, knowledge and understanding improves people, and knowledge and understanding of a field of endeavour improves the practice of that endeavour.

It is also a most extraordinary approach for a person who is largely known as a performer of traditional songs and other music - how would one know it was traditional unless there had been an analysis?