I'm a bit torn about this, is calling someone a name prefixed by the country of their birth a racist slur. Is polynesian a race. Theoretically you could be a white, black or any other race but still polynesian. Similar to if you call someone an English, French person a slur prefixed with the nation of birth.
I actually find it weird he called him that in the heat of an argument and would have thought had he meant it as a racist slur he would've just used colour as a prefix. Not condoning it just trying to see the angle of it not having to come back to race or him being a racist.