First off, this will never be banned. There is not 1 government agency that I know of that would want to open that pandoras box. But to get to the point..
My family is a mix of Irish and Italian. Being stuck in the middle of both (as I am a hybrid Italian and Irish) I can get away with referring to others as "Mics" or "Guido's" simply because my own heritage represents both cultures. However if either side refers to the other with the same slur, you better be ready for a fight. I dont know an Irishman or an Italian that would let either get away with throwing those words around.
I have never come into a situation where anyone thought it was ok for a black person to refer to someone from mexico as a "Wet Back" However, with regards to the term "Cracker" I dont think it holds the same connotation as the "N" word and I believe that other whites like myself feel the same way. Actually, I think its quite funny.
So why is it that you must single out blacks, or specifically, black Americans, when there are so many other people in this country who get so easily offended by words that are not nearly as representative of the negative connotation of the "N" word.?