This reminds me a touch of MacColl's Critics Group insistence that singers should restrict their repertoires to their authentic geographies of origin - whilst himself being a Salfordian wrapped in ancestral Scottish heritage, singing songs from right across the realm, and a prolific writer of new material to boot.

As in so many fields, the high priests are above the covenants required of the flock...! quote Black Acorn
According to Jim Carroll, who knew MacColl   well, that was not the case, it only applied to people singing at the singers club, neither did the rule apply to writing new songs.
MacColl was born in Salford, his mother was Scottish, According to wiki his parents were Scottish, WIKI IS NOT ALWAYS ACCURATE.
A TYPICAL BIT OF MACCOLL BASHING AND HAS NO CONNECTION WITH LLOYD AND SEA SHANTIES OR LLOYDS SCHOLARSHIP OR LACK OF SCHOLARSHIP