> I'm somewhat surprised that a jazz scholar would overlook the possibility that the tropes used to promote black music in the early 20th century could be deepl

> I'm somewhat surprised that a jazz scholar would overlook the possibility that the tropes used to promote black music in the early 20th century could be deeply derogatory From the paragraph before the one you quoted, I think the author's claim there is that "jazz" wasn't (at that point) being used to refer particularly to black music, so it follows that it didn't do so derogatorily.