Everybody stop talking about how he used the n-word. This isn't about the n-word. If that's all you heard, you weren't listening. Yeah, he used the word and seemed to be quite proud of himself for doing so. Whatever. What you should have been offended by was the braggadocio he exhibited as he talked about a brother being strung up. That was uncalled for, was it not? If you can't handle heckling, you shouldn't be a stand-up comedian. Dealing with that mess is part of the job. Many a stand-up has put a heckler in his place without going where Michael Richards went.
Some things just aren't funny. They will never be funny. This was one of them. As for his apology, he need not have wasted his breath.