Suppose the objection against 'ripp(ing) loose (a folk song) from the manner in which it was traditionally sung' were applied conversely, and folk musicians were prohibited from ripping loose popular songs from the manner in which they were sung? The body of folk music would be reduced greatly, at least in the U.S., if you were to cast away every song that originated in the minstrel shows, or as a parlor song composed for sheet music sales, or as a song written and recorded for the main purpose of selling records. As for restyling songs, I'm glad some banjo player 150 years ago got a notion to speed up "The Cuckoo" and brighten up the lyrics, and that Robert Johnson got the idea to make the ancient "Hangman" into a blues number. That's continuing to happy today, but it'll be 30 years or so before anybody can declare what worked and what didn't. I suspect the tradition will continue on two tracks: 'preserved' folk music and 'practiced' folk music, which is open to contemporary influences. Long live them both.