they operate undercover most of the time

Maybe so, but all I've been able to see is clubs and singarounds where nobody and nothing is disapproved of or treated with intolerance, and the folk umbrella can shelter pretty much anyone who wants to come in under it.

Anyway, Al didn't say "there are people out there who hold rigid ideas about what constitutes folk in the privacy of their own heads"; he said the scene's full of people "opining - this isn't folk music and that isn't folk music". To which I can only say, in my experience, no it isn't.