A music or custom that ends up standing for a whole nation does not rise there on its own. It gets there through a long series of dealings between rich and poor, powerful and weak, who often want different things from it. The story that it simply surfaced one day hides who did the work of lifting it.
A cultural form can read one way to outsiders and another way to insiders. Foreigners hear this music as a display of a country's African roots, while people inside the country hear it as proof that they are a blend of races and cultures. What a symbol means depends on who is looking.
The usual account says a scorned music of the poor changed suddenly and mysteriously into something everyone loves. Calling the change a mystery is itself part of the story a nation tells about itself, because it skips over the deliberate go-betweens and trade-offs that actually moved the music up the social ladder.