A native of the state of Ohio that is a fan of the University of Michigan's football program.
The "blue" part of the word stems from the fact that U of M's school colors are maize and blue. Also, its fans will cheer, "Go Blue" to show support for their team. The "blood" part is meant to define the emotion of passion that all people have to some extent. As a compound word its intent is to imply that a blueblood's passions are somehow tainted and/or inappropriate. Transversely, Ohio State's school colors are scarlett and gray. As most Ohioans that watch collegiate football are supporters of the Ohio State Buckeyes, and as Michigan is Ohio State's archrival, the term is intended to express a negative, ostrasizing connotation.
" We don't want you bluebloods here anyway! We don't give a damn for the whole state of Michigan!"