In fact, there were under remembered Roma "Gypsy" bands all over the US in the early part of the century, bringing Klesmer-like music to all the corners of the nation... I think Ken is not stupid, but as one of the other posters said, is presenting a poplular primer... Conrad, could it be you are pissed because he forgot to mention that old rag, "The Orange Order Stomp"?
Just pulling your chain, ol skin
I noticed the Irish ommission as well, though I think his focus was to set up the end of the show for the White Guys invented Jazz nonsence of the first recorded Jazz band, artisitic licence in film often puts a spin on history, that is what books are for...
Cheers
Larry