In reading the comments to this post I was moved to comment on the ad hominem fallacy. An ad hominem is not synonymous with an insult. Any argument that takes on the individual making the argument rather than the argument the individual is making is an ad hominem. That’s just what it means.
Consequently, this statement:
I think Megan is often right, but also often tends to bend things a bit, in an ideological direction.
(It would be a misuse of the term to say that sentence just above is a “ad hominem” though, to the extent that it might be true.)
is poppycock. The truth of an attack against the individual making the argument has no bearing on whether it’s an ad hominem or not. If it’s an attack on the individual rather than the argument, it’s an ad hominem. This is what comes of people using Latin rather than English. In Latin ad hominem means “to the person”. as opposed, presumably, to ad argumentum, “to the argument”.
If an ad hominem attack is not true, it is a slander. If it is irrelevant, it is a fallacy.