A former co-worker is ethnically Persian but grew up in Belarus so he has a vaguely European accent.
When traveling, he likes to wear a shirt that says "Italia" because when airline security thinks that he's Italian, he gets less hassle.
My anecdotal evidence is in accord with this.
During the last few months, I have let myself have a beard. I have a darkish skin, so with a beard I look very Arabic.
In my last flight, security were specially bothersome, making me open and show my luggage. I didn't relate it until my friend pointed it out, but I am very sure he was right now.
I agree about referencing the word "nigger", Louis CK has a bit where he says he hates the phrase "the n-word" because, "you still put the word 'nigger' into my head, so it's not like you didn't say it".
But socially one probably has to accept reality, there's a court case about a guy who was fired for saying the word, not using it in a derogatory way but just referring to the word itself.