The verse starts:
"Black cat is bad luck, bad guys wear black.
Musta been a white guy who started all that."
Interestingly, the MC in question here is white-skinned. I think he's Jewish, but I might be wrong.
From the perspective of an African immigrant, I would imagine that it is easy to see discrimination everywhere. I think your friend is annoyed that the idea of "blackness being inferior" is omnipresent (from his perspective). It's even built in to the very way we speak.
I think that what your immigrant friend really wants is just to feel like he has the same shot a person with white skin does. He's kvetching about words because racism is on his mind a lot, but he's not expecting you or anyone to rewrite the English language. He probably just gets treated poorly on a regular basis because of his race, and he wants that to stop.
You (We) could likely cure his annoyances while stopping short of major linguistic changes.