I'm not suggesting ignoring it. Ignoring it is what happened with the Palin thread, until it became a complete train-wreck and now we have this thread.
A post in response to say something along the lines of "if you were trying to be funny, it wasn't" or "if you're being serious then -<insert serious argument here>-" would let everyone know that you think there's a problem.
EDIT: To be clear, I know you, Nerys Ghemor, did do that in the Palin thread - but in general, I'm not suggesting ignoring what you find unacceptable, but giving the benefit of the doubt and then raising a question of "is this a joke?" to allow a chance for apology.