Let me hasten to add that you're not entirely wrong. When you look at the reliability of a source, it's important to be clear in your own mind on the difference between an ad hominem argument and the legitimate challenge to the foundation of an argument based on an often unstated premise to expertise, and subsequent opinionating. And if it's clear in your mind, you have to find a way to make it clear in your writing. And even then, the audience or opponent may not follow you. If there's a sound argument that doesn't require so much stage-setting and invite so much misinterpretation, you're often better off making that one instead. I looked at the link, skimmed the article, skipped to the footnotes, and realize it would probably take me 3-4 days of full-time effort to find all of Bennett's material omissions, misinterpretations, and bad guesses. She bets on people not being willing to do that. She bets on people just buying the gallop. Dark Moon is 350+ pages long, mostly so that you can't read it all in one sitting and thereby catch all her contradictions and missteps. This is who she is. This is what she does. It's difficult to shame her into honesty because she knows what she's doing and doesn't care what you think. You're not the intended audience, so she has no use for you.
Maybe some more helpful advice would be not to be baited into accepting a burden of proof that's not yours. If the claim is that all the Apollo records have been rewritten to describe a different trajectory, make your opponent prove that. He has to show the numbers were once different than they are now. His is the affirmative claim. His is the claim that's trying to rewrite accepted history. When it comes to the source, make him defend its reliability. Don't fall for the gambit that the only way you're allowed to refute it is to take it at face value, to argue a counterclaim affirmatively, or anything else that puts all the work on your shoulders. The question I typically ask is, "What process did you undertake to ensure this is a scientifically reliable, factually accurate source?" It's self-published on a crank website by someone who's made her living for years screaming at Apollo from the shadows, allowing herself to be subject to practically zero effective criticism. Objectively, that's not a good start. If he hasn't done anything to verify its claims, then he's the one who needs to do homework, given the circumstances surrounding the claim.
This is often the sort of argument you have to deal with. They get to play silly rhetorical tricks while you, for some reason, are the only one mandated to play it straight. Mary Bennett is not a reliable source of information on the history of space exploration. That means something. It's up to you to make sure it means something that obligates them to defend their use of her material.
