yeah of course blues [which is a form of American folk music],is one of the mothers/fathers of jazz.
I agree nothing is black and white but somewhere there has to be demarcation lines.
My kind of music would not be acceptable to most of the punters in a Country Western club,they want C/W,not folk,not jazz[possiblywestern swing excepted].and in folk clubs and folk festivals,we dont expect Opera or CW,Although Bluegrass might be acceptable now and again.