I mean, I want to give him the benefit of the doubt, because even Rick Santorum shouldn't be this stupid, but I can't really think of a logical explanation as to what else "nig..." could mean.
Boo this man.
UPDATE: The spirit on tumblr seems to be one of barely-contained glee. It's like everyone's been waiting for Ricky to say something really fucking racist. I think that reaction might be the best part.