Who he called a N-word is irrelevant. It's the underlying connotation of the word itself. The word is a term of disparagement of the black race. Period. When used by the race that brought it into the English lexicon knowing and being fully aware of its function, history, relevancy, context...you then are ignoring the pejorative nature of the word and it is that willful ignorance that does not absolve you from being called racist.
To sum up....you know it's wrong and you do it anyway = racist.
And it's made worse because he is basically saying white people are superior to black people. He said a white person of poor action/thought is a white N-word. He was calling them white-black people. As though being black is a bad thing to be.
I can't believe we have to explain this stuff. This is why this shit has persisted for so long.
And this isn't about free speech. It's about a violation of the Terms of Service which I've already linked to. Further that, you don't have free speech like you think you do. Freedom of Speech in the US is merely the freedom from the government from censoring or denying you the right to speak. It doesn't mean jack all for private enterprise (which is ironic given how the right wants private enterprise to set rules as they please).
No, intentionally using the N-word does not automatically make you a Racist. There are exceptions for black people, in art, etc.
Look at it in this way, in Germany it is forbidden to use the swastika but even for such a hard law exceptions exist.