I can understand someone like Charles Wesley taking a tune that every one was singing and setting a hymn to it. (If I remember right he set Love Divine to the tune Fairest Isle, saying "Why should the Devil have all the best tunes?")
I am shocked to read in my new copy of 'english dance & song' that Vaughan Williams, who edited the English Hymnal was never a professing christian but wanted English folk tunes sung, and thought that setting hymns to them was the best way to make that happen.
Does anyone agree with me that contaminating our musical heritage with religious sentiment is, on the whole, a bad thing. Some tunes (e.g. To be a Pilgrim) have become so wedded to the hymn that to use them for the origional words seem like borrowing.
(My viewpoint is ex-Christian)