He was saying your analogy is bad because "black" is an English word, and you were - in your Japanese example - encountering people speaking a different language. People can correct me on this if I'm wrong, but I'm assuming the word "Arab" in Arabic would be, if not completely different, then at least pronounced differently than what Khalil and people are fighting for in this post...

I'm still of two minds about this whole issue but I wanted to clear that up. No one said to pronounce it like it's pronounced in Arabic. That's why his "blackie" comeback fits.