The "word" in general is racist regardless of whether it's common spelling or slang spelling. You can't say spelling it with an "a" isn't racist.
Its only racist if you're racist. I am not therefor I do not think its racist for me to use it as humor. Unless I directly used it towards someone, it shouldn't be a problem. If it weren't a rule not to use it, I would keep on with the thread as I planned.