Wesley,

Blues is extensive from Blind Lemon Jefferson to Charlie Parker. Blues is a staple of jazz.

Folk music is all over the world with different harmonies in their music, some emphasizing harmony, some melody.

Bluegrass is a small tributary of Appalachian string band music.

That said (as the newscasters say) I like bluegrass music and see it's value as part of
a bigger picture of Anglo-American folk music with Irish, English, and Scottish roots.

What I object to is the narrowing of the style and the phony association that some have with it. There is no such thing as a pure music. It all contains influences from other forms.

Thank you Mark.