i agree with him 100%. the only thing i'd add from a realist perspective is the following...
anyone can say anything they want. we all have mouths and can do that. something thoughtful people should be mindful of is the way certain words make people feel, or what saying certain words can incite in others. there's two solid reasons for people who are not black not say "nigga," that negate any rationalization regarding where someone grew up, or how many times they've been to jail.
› how the word makes people who the word applies to feel
› what you saying the word can incite in people to do to you
if you're concerned with either of those things after you have realized that they're both real and legitimate reasons not to say the shit will dictate whether or not you say it. this principal applies to any word that objectifies a people, regardless of how the person means it. it applies to words like, "nigga" but it also applies to words like faggot. it doesn't matter how the person saying it means it, if they aren't black, their perspective is irrelevant as far as rationalization goes. but if they wanna say it and don't give a fuck about making people uncomfortable, or the consequences of what happens when you make the wrong person uncomfortable, then go ahead and say that shit and deal w/it when shit pop.