I don't care to define what is "authentic"... Seems to me that someone(Huddie Ledbetter?) once said it best when asked about the definition of folk music:...something about, "it's all folk music, never heard a horse sing ".
As you can tell, I play what I like--that's my only criterion.
Categories are for scholars--essentially defining something that is in the past,and not dealing with the irreverence, freshness and experimenting of the now.