"Seems to be a generally known fact that Sharp more than likely "cleaned up" the songs he collected."

'Generally known' by whom, exactly?

"So, does it really matter now...?"

Yes, of course it does. Anyone who claims to be performing 'traditional song' needs to know whether what they are performing is actually traditional or a second-hand retread of something that The Rev. Baring-Gould, A. L. Lloyd, or whoever, decided was more interesting than the real thing.

And you'd have hoped that a significant new, tradition-based project like 'Imagined Village' (CD not book), which boasts a stellar cast and many interesting collaborations, and claims to be part of the 'search for English identity', could do better than advertise itself with an opening paragraph of absolute cobblers.