"he ranted about Buchan's versions and used them as a last resort."
And as has been pointed out by Hustvedt and others, Child later had cause to reconsider his attitude.
Having just read William Walker's article on the controversy, I have become convinced that the 'Buchan controversy' was largely due to with the fact that Buchan's findings didn't suit preconceived attitudes and pet theories, and that seems to still be the case.
Still a controversy, but would highly recommend reading Ian Spring's excellent introduction to 'Secret Songs of Silence'
All the early anthologists tampered with the songs.
Jim Carroll