Surely you can appreciate the unique power of the N word. There is a lot of history and hatred contained in that word. I don't think there is another word that comes close in terms of explosiveness.
I think that's why Richards used it. Obviously, he was pissed off and he made the terrible mistake of letting all of his rage out at once in the most shocking way he knew how. I think what he did was just plain stupid. Stupid and wrong. He knows it too. I think he surprised himself by how much rage he had. I don't think he's a racist, but he did use racism to vent his anger. That's a dangerous thing. It's not comparable to Don Rickles and it's not comparable to Lenny Bruce. It's much worse.
Having said that, I think people should accept his apology.