Thanks to those who have posted on this thread.

I'm glad to know as Lox put it that "The important thing is the accumulation of knowledge and the advancement of the artform, not the ethnicity of those who have worked so hard to develop it."

However, I dare say that this same disregard for race was not the norm among most of the jazz musicians' audiences, the nightclub owners, the radio hosts, the movie producers etc.

For instance, I suspect that although jam sessions at juke joints or wherever might occasionally be integrated, the paid gigs were rarely if ever integrated. And I suspect that the "King of Jazz" movie only featured White musicians.

Which leads me to the same conclusion that mainstream American [USA] society would have been {and probably still is to a lesser degree] unwilling to confer the title of King of Jazz on a Black man.