What black people are offended by the use of the word nigga? He even said it the way it is said in normal context. He didn't call anyone the word. He just said it within the proper context.
Your first link has to do with the actual N word. Nigga is used once in there explaining how blacks call themselves the word.
On the second, here is a quote from your own link.
The context was fine in this case.In practice, its use and meaning are heavily dependent on context
Character assassination ftl.
Argue the points, not the poster.