Jazz/Blues Lecture and Ray

I honestly really liked the little bit of Ray that we watched. I had heard great things about that movie but just had never thought about watching it. I did enjoy it though. So I am a fan of blues. . . well I like the sound but I never really learned much about it. My dad was fan so through him I heard songs and such. This may be a stupid/random question. . . but why is there such a deep rooted connection between the Devil and blues? I mean yeah I've heard that story about the blues musician who was so talented that rumors began to swirl about that he sold his soul in order to be able to play so well. I think there was a movie following that pretense starring the Karate Kid (Ralph Machio). But why Blues? Why are there hardly any stories that centre around a Jazz singer who sold their soul for a better voice? Or how about the pianist who sold their soul in order to have nimble finger? I guess it could be based on the fact that blues was primarily based in African American society (I guess I mean took off and/or was started). Maybe the response by the white community was to "satanize" Blues? Perhaps because the African American community is a deeply religious one, especially the in the deep south during the early-mid 20th century and that, along with envy, made way for a nasty little rumor to come out. But that still leaves the question unanswered. Why Blues? If anyone could tell me that would be lovely!! Also, one last disability point erm. . . question. . . what's the difference between crip drag and black face? Aside from intent isn't the point of both to transform one so completely that they are essentially the inverse of what they actually are? Both roles tend to be stereotypical and over exaggerated to get the point across. If you ask me they're in the same category.