Academia has taken over the folk-world. There are those who insist on a "correct" approach to folk music as if there were hard and fast rules. A study of comparitive musical styles reveal a lot about what is "correct" or not. For every traditionalist from a specific folk culture there are anomalies that don't fit in. It's like looking at anthropologic monographs and deciding that they are frozen in time and haven't been subjected to outside influences.
The compartmentalization of folk music is an academic construct and not entirely honest. There is no "purity" in folk music any more than there is racial purity. A knowledge of folk music styles is fine as long as it doesn't become a tablet "writ-in-stone". But there is a lot of artiface and sham in the folk music field by those claiming to know more than others about their respective musical styles. Generally, the people who emanate from a particular tradition of music based on a folk-culture are not aware of the academic aspects and see little difference between what they do and what others outside of that circle do. I think it's a healthy thing to mix up styles of dance and music although it doesn't hurt to discover musical and historical knowledge about these various forms of stylistic expression.
Emulation of a favorite musician or singer is a valid learning tool as an insight into folk music but at some point it becomes necessary to escape from the copy-cat prison and establish an original "voice". It sort of happens naturally because if you try to duplicate exactly what someone else does, it's a prescription for failure. It'll never happen. Even the best imitation will always sound like that...an imitation.
But trumped-up "authorities" abound in every field and their value is only as good as the information that they provide which is never totally accurate because folk music scholarship is not rocket science.