Dave, I suspect that this is what caught Johnny's eye:

Yes! Why didn't Jazz evolve in africa especially parts of Africa which were multi cultural or connected to trade routes. North Africa near spain would seem to be an ideal candidate. As in early midaeval music you find folk quite well connected via trade and troubadours etc...

Or maybe it was just the water!

(The above excerpts from one post, put here to show context for the following post.)

Or could it be that watermellons of a certain type only native to north america are essential. :) ;/

Presumably the "water" and "watermelon" lines were tongue in cheek. I would guess that the "watermelon" part was more tasteless than racist in its motivation, but it speaks to me of a degree of insensitivity to those who have been victims of racist attitudes, some of which included "watermelon" references.