Is the point here that the very structure of syllogism itself can be denied? That however inexorable a "If A and B, then C" argument is, someone else could always argue that it's not quite valid yet? It kind of reminds me of the point made (turgidly, but still) by Yudkowsky in The Simple Truth[1] - sometimes you just have to throw up your hands and declare the counter-arguments specious.

[1] http://yudkowsky.net/rational/the-simple-truth