If I were him, I would have said something like this:
"Look, you fuckers all bitching and whining when we went into Afghanistan and Iraq, especially as we did it without a UN mandate.
"The UN—corrupt as it is—has decided that there is no genocide in Darfur, just some "war crimes". Under those terms, the UN is not obligated to interfere.
"And frankly, if you expect us to help out after all the attitude that you've given us, you can fuck right off.
"You want to do something about Darfur? Well, you go and petition all of those evil tyrants, dictators, despots and religious loons in the UN.
"Count us out: we have neither the money nor the troops nor the inclination to salve your pathetic left-liberal consciences.
"Fucking do it yourself. Or maybe the EU could ha... Hahahahahaha! Sorry, couldn't help it. I was just remembering the EU's effectiveness in the Balkans. Aaaaahahahahahaha!"
That would have got the message across, I think.