the ad hominem fallacy fallacy

Debates on the internet tend towards flame wars; however, “if you can’t demonstrate that your opponent is trying to counter your argument by attacking you, you can’t demonstrate that he is resorting to ad hominem.”

“Those who are quick to squeal ‘ad hominem’ are often guilty of several other logical fallacies, including one of the worst of all: the fallacious belief that introducing an impressive-sounding Latin term somehow gives one the decisive edge in an argument.”

A might be wrong, but B’s reply is not Ad Hominem:

• A: “All rodents are mammals, but a weasel isn’t a rodent, so it can’t be a mammal.”
• B: “You’re an asshole.”