Silas - re-reading your post, I can see that I have misinterpreted it, so I apologise for that. You were not being as exclusive as my first reading of your post made you seem to be.

I would, however, state that if you are not welcoming to what you call 'World Music (whatever that is)' then you are missing out in a big way.

Folk song, traditional song, does not end at the Straits of Dover. Again, quoting the example of the club that I run, in the last few years we have had guest performers on tour in this country from Zimbabwe, Hungary, The Gambia, Roumania, Sierra Leone, Breton-speaking groups and French- and Spanish-speaking groups from the North American minority language areas of Louisiana, Quebec and New Mexico. These nights when our locals have tried to present the best of our culture against the musical riches that our foreign guests have brought with them have been amongst the most rewarding of all our presentations.
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Last Thursday we had an American with an Appalchian background as guest. I don't know how old Kate Lissauer is, but young enough to be my daughter if not my granddaughter. I started off the evening with Jeannie Robertson's version of The Gypsy Laddies which I have always thought of from the gypsies' point of view because of my long enthusiasm for Scots Travellers and their culture. I see it as a song that just gives one example of the cruel treatment of this outcast minority. Then Kate got up and said, "I'm going to sing a different version of the song that Vic sung earlier; this is from my area and is called Black Jack Davy, For me, this song is about a woman having a mid-life crisis. We've all met people who seem to have a settled, happy life, then they go off the rails with an impossible relationship that cannot work, haven't we?"
Brilliant! Fascinating! For me this was a new insight into a song that I have sung for decades; just what I want to get from a folk club evening.