It's too bad Rok is not still around, I considered him the authority in our circle on "The Blues".
Ghosthouse, with the Blues, you have to go by what you hear, instead of what you read. Roc said almost all singing Blues is Delta Blues, and he was right, because if you listen, so much of it is the same music with different words.
I imagine what you have posted is from some "authority" who probably knows less about the Blues than you. The people most responsible for "Guitar Blues", yelling, howling, screaming, crying blues, could, neither read nor write, and they go way back.
If we're going to talk about the blues, we should have a better definition of what we're talking about.
Enjoy the music, and I guess that includes, "Da Blues".