"Nigger" was coined by whites to denigrate blacks--just like "Boy" and a dozen other terms. Its use by blacks is ironic, its use by whites communicates hate. Willfully refusing to accept that a word intended to communicate white hate would strike blacks differently than it strikes white, well, yeah that is racist.
Yeah, you see. I am white. I didn't coin that word. I am not even American. There is basically nothing that connects me to black slavery except the color of my skin. My family roots go back to slaves too (like roots of >99% of people). I used to use this word ironically to demean pervasive hip hop pop culture. Thankfully, I am no longer in high school and don't have to talk to people who listen to songs about gangsters and fucking bitches.