he was merely the passive object of it

To think of the creative genius of Purcell being passive in any sense is as absurd as the whole concept of 'the folk process' - by which all such genius must indeed be passive, or yet Anonymous. I'd say the 'Folk Process' is, like God, a matter of first interpretation and second, illusion. All music is the consequence of creative traditional flux, and yet this 'folk process' is considered (by folkies) to be somehow unique to folk. Or is the 'folk process' merely the way Folkies take things and make them 'folk' by slowing them down, as is the case here - or speeding them up, as is (invariably) the case with (say) Music for a Found Harmonium?

For sure, we are free to do anything we like with whatever we like; it's simply a matter of interpretation, which gives rise to convention, there's nothing passive about any of it - on the contrary, from the creative of the piece in the first place (whatever Purcell's source might have been) to to individual musicians who play the thing today. You can see the same thing happening BTW with Frank Zappa's Black Page on YouTube - methinks it's bound to end up as a session tune one of these days, slowed down of course!