So, several years ago, in first immersing myself in the atheism-religion/evolution-creationism debates on YouTube (back when they were the thing) I was introduced to the idea of logical fallacies. It popped up everywhere, and I'd always hear "ad hominem" this, and "strawman" that; "appeal to consequences" this, and "appeal to authority" that. But one method of argumentation I heard, and continue to hear with increasing frequency, is an appeal to hypocrisy. One side will point out the inconsistency between the other side's positions, or the inconsistency between the other side's position and their behavior, in an attempt to demonstrate something (I have no fucking idea). And I'm sorry to say that I feel that I hear this mode of argumentation more from the atheist/science-promoting/liberal side (my side) of debates than their counterparts. It baffles me that people—otherwise rational people who are aware of logical fallacies—continue to do this, as the appeal to hypocrisy is a universally-recognized logical fallacy.
It should be obvious that the appeal to hypocrisy is fallacious; I figured it out before I knew it was categorized as a fallacy. A person's inconsistency between her positions, or the inconsistency between her positions and her behavior has absolutely no bearing on the truth or falsity of her positions. Appealing to hypocrisy is ignores the opponent's position and rather attacks the opponent herself. Thus, it is a form of ad hominem, which in turn is a non sequitur—an argument that has no logical connection to the discussion at hand.
Sure, it can be fun to point out people's hypocrisy. People get away with the fact that their hypocrisy can be subtle, or that their contradictory positions are laid out so far from one another that the contradiction is harder to detect; thus, it's all the more satisfying to lay out someone's contradictory positions right next to each other so the contradiction is undeniable. It is fun. But it's so fucking easy. And I would back that up with the fact that I fucking see the appeal to hypocrisy everywhere, from all walks of life, in so many different contexts.
Not only is it easy to expose hypocrisy, but it's easy to exhibit hypocrisy. Everyone is a hypocrite. Managing cognitive dissonance and holding contradictory opinions and behaviors is something humans are notoriously good at. We rationalize, we deny, and we ignore so we don't have to think about it. Thus, the appeal to hypocrisy isn't even a good ad hominem, because hypocrisy isn't something that takes a particularly flawed or dishonest person.
But you know what's not easy? Explaining hypocrisy. Confronting hypocrisy. Admitting hypocrisy. Ignoring hypocrisy and actually addressing the opponent's arguments.