Mr. Bad: “As for…
Mr. Bad: “As for Arwen’s ad hominem against Richard, I’m slightly surprised that you let it slide; I thought personal attacks were out of bounds here.”
This is something of a pet peeve of mine.
The fallacy of argumentum ad hominem is committed when you (irrelevantly) appeal to facts about the person advocating a view or advancing an argument, as a substitute for addressing the argument. In its circumstantial form, the appeal points out properties that are supposed to explain why the person is making an argument, and tries to use them to explain away or dismiss the argument. In its abusive form, the appeal points out properties that are supposed to make the advocate bad or untrustworthy, and so to dismiss or undermine the argument without considering it on its own merits.
Argumentum ad hominem is not committed whenever somebody insults another person, or engages in “personal attacks.” (It is only when the attacks are insults are falsely presented as a counter-argument to some point that the fallacy is committed.) Arwen didn’t do this to Richard. In fact, she didn’t engage in any personal attacks at all: she merely used sarcasm to point out that the standards that he was applying to the feminist movement, and to feminist theory as a whole, were unfair.
Hope this helps.