...which readers periodically send me is, in fact, full of mistakes and careless formulations, which is why I've ignored it so far. Take the mistaken definition of "ad hominem": "Attacking your opponent’s character or personal traits instead of engaging with their argument." But it is only fallacious to argue from facts about a person to the truth or falsity of what they say; it is perfectly reasonable to infer from facts about a person to whether or not they are a reliable source, such that what they say gives you warrant for believing what they say. There is, of course, no general logical or even epistemic obligation to engage with someone's argument.

Pretty embarrassing mistake, given the subject!