It was quite the opposite of that, in fact...

Hip-hop was the cats that was "cool... but had no groove" that George mocked in "Music For My Mother." And George later said that hip-hoppers (at least by the early 90s) reminded him of Sir Nose, or of white people and suburban Blacks.

Actually, I think I'll agree with you... Hip-hop was not rebellious per se, but it was revolutionary. It upturned the entire Black music status quo but I don't think it even did so deliberately.