A horrible disease that, once contracted, is incurable. People with Al Sharptonism think that EVERYTHING is racist. Other symptoms often, but not always, include being wider than you are tall, having a hairdo that hedgehogs would consider excessive, and talking in Ebonics.
My favorite Al Sharptonistic phrase is "My black brotha' just tripped over a stick! The tree that dropped that sick must be a KKK member! Arrest that sonofabitch evergreen before his racist ways infect the entire population of the Divided States!"