I'm all for low-brow off-color humor, but there comes a point where a joke, even stated "ironically," isn't funny. Yours isn't funny, and it's because it lacks context. Over half your post is devoted to an inappropriate joke that doesn't have anything to do with your point. The fact that you have to throw a disclaimer in there should have been an indication that it isn't funny. Racist humor can be funny (in my opinion), but not when it's delivered like a knock-knock joke.