So, what should you do if someone keeps calling you a crypto-nazi in a televised debate? I'm pretty sure that if Buckley and Vidal had been having a debate about civil rights, and Buckley repeatedly called Vidal a "crypto-faggot", under the pretense that doing so was vaguely related to civil rights, and then if Vidal had made a rejoinder similar to the one quoted, you'd be applauding it.
Remember, it was Vidal's essay about Buckley that twice inspired libel suits and forced Esquire to print an apology.
(Note: Not a Republican and not a fan of Buckley, but a fan of the truth.)