No one needs to lie. Your argument reminds me of the infamous discussion at Femecon, when Doug and Katha Pollitt defended Barbara Ehrenreich's work in Nickled and Dimed.
First, Doug was attacked by several economists who asked how many millions he'd earned from the book, Wall St., and needled him about likely having a wife who did the housework. Next, someone red baited Katha Pollit.
No one lied. They were simply using unprincicpled debate tactics.
The upshot was: no one had to actually read Ehrenreich's article. It was easier to discuss Doug's wealth or lack thereof or whether or not Katha was a Red. No matter what either of them did, they were screwed.
Michael Smith:
You've lied, haven't you? I don't mean you-you of course, but the imaginary you of your hypothetical case.
An ad hominem is one thing. Smith knows Latin and owns a little sailboat, so clearly he knows nothing about the Working Class. None of the factual claims is a lie, but it's still a fallacy, and even as rhetoric, a feeble line of argument at best -- hardly worth refuting. Nobody is really convinced by it who isn't already convinced.
But a lie is another thing, and a lot more serious. Somebody might be convinced by a lie.
You're quite right to say, though, that refuting a lie may cost more than it buys you. The locus classicus is that anti-Semite thing that Zionists love to deploy. If you turn aside to answer it, they win. But if you don't turn aside to answer it, then they go unanswered.
I think you just have to laugh it off, and wait until the gambit has become so familiar and tired that nobody pays any attention anymore.
Henry Ford, I believe, once said, "never explain, never apologize." Not bad advice, though a little over-generalized. I'd say, with Gilbert & Sullivan, "hardly ever".
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