Richard Feynman is known to have a temper, and Einstein was known to be extremely callous in intimate affairs. We've also seen MIT professors display a lesser regard for lesser minds in math. We've also seen brilliant top-of-their field sportsman display great arrogance and disregard to lessers. The guy who writes "The Haskell Book" isn't known to be nice, but people still acknowledge that it's one of the top texts. Linus Torvalds isn't known to be nice.
You might not consider these people to be "geniuses", but they are certainly brilliant in some way, participating heavily in their field in some way.