If people want to call it racist that's fine. But don't twist his words around to make it worse than he really is. He didn't call him a black butthole.
That's all find and well but why even bring "black" into it. It's 2011. Everything is racist. Whether it was meant to be or not. One thing I preach to my staff is "perceived reality" and actual reality isn't going to be what people perceive when you make a stupid comment like that. Call him a cheating butthole or a stupid butthole. There was no need to even say "black" in that comment regardless of who he said it to. Obviously it wasn't to anyone that cares enough about him to not say something.