This song brings into focus the issue of copyright. THe question is: when does a song become a variant of a known song or when is it re-written using only a lyric theme or a basic tune?
Having been associated with "Paul Campbell", I know that some songs that they do have been changed radically from their source.
That's because "Paul Campbell" contains songwriters.
"Delta Dawn", a popular song from years ago uses the same tune as "Come and Go With Me To That Land". There are many such examples. "The Twelth of Never" from the fifties based on "The Riddle Song".
Then there is the controversey surrounding Paul Simon's popularizing "Scarborough Fair" which some say was taken from the arrangement by Davy Graham. But the "Canticle" part was Simon's own creation.
I'm not sure but I would guess that the Weaver's version of "The Drinking Gourd" would be quite different from the source.
When does the artist re-create the song and when is it stolen? The "moral judgement" about such matters is murky im my view.