The woman making the claim isn't, as far as I can tell, making an argument on this point. She's making a statement. In statements the credibility of the person

The woman making the claim isn't, as far as I can tell, making an argument on this point. She's making a statement. In statements the credibility of the person making the claim is important. Like if I lied every single time I spoke, and you knew me to do so, and I said that I definitely was going to give you £100, you would be right to be sceptical of me. Nost arguments have two parts: Factual claims that may or may not align with how the world actually is, and a logical structure. If X then Y, X therefore Y. Would be an example of one such structure (modus ponens being the underlying rule.) Another example would be If X then Y, not Y therefore not X (modus tollens.) Something where the structure is an example of a way of reasoning that preserves truth values is called 'valid,' and something where the structure does so and the claims that are made using that structure are true is called 'sound.' Now if I, being an always-liar in the original assumption, used one of those structures, my character would have no bearing on the validity of the underlying logic. The example of logical form would either be a valid way to argue; preserving the truth states of my predicates; or it wouldn't. And one can lie within the constraints of a logical form or not. 'Logic is true of any world, so it doesn't tell you where you happen to be.' Likewise, it is incorrect to say that when someone just lies a lot that their character absolutely means that what they're saying will always be a lie. So you can't directly state that because someone's character is low that when they use a logical form they are, of necessity, expressing something false. In these latter two senses it would be a mistake to equate - on a 1-1 basis - the soundness of someone's argument with the content of their character. However in the latter of those two senses, it is only a fallacy to state that someone's argument is equated on a 1-1 basis. It is not a fallacy to say that someone, for example, lies a lot so the claims in their argument are less likely to be true. So, someone comes along and makes a fairly direct claim and someone challenges their credibility, saying that they'd take it with a pinch of salt because the claim favours what they take to the claimant's previously expressed political interests. That's not a fallacy. If they said that she was obviously lying, then that would be more than is warranted by the evidence, but the form of the statement they're making isn't an example of an ad hominem fallacy.