When I was first seriously into British Traditional Jazz I was a most definate Purist - NO saxophone , NO Guitar , NO Piano ! Just trumpet clarinet trombone front line and banjo bass drums for rhythm ! Then I bought a reissued album of Louis Armstrongs first recordings with King Olive - March / April 1923 !! Lil Harding on piano , johhny StCyr playing a Six String banjo tuned as guitar and Stump Evans on Alto Sax . Stopped me being a 'Purist' on the spot !
It seems to me that far too many people who qualify for the 'purist' label in Folk simply havent opened their ears and their minds to enough good music !!