Alan, here's where you need a lesson in arci-logic. You will never get thru to him in any argument or disagreement. He for some unknown reason, has told himself that he's "smarter than the rest", so whatever you say & however you say it, he simply will not ever allow it past his do-not-accept filter. Doesn't matter how right you are or even if you have absolute factual backup as you do here. As a geek he's a veteran of being continuously picked on, and whether or not you're doing that to him here, he only sees it in one unequivocal way.
Of course, you can always make fun of him and then wait for the personal problems to die down again before he comes back on....