Here's the thing. Both with the religion argument and in general: even if you're right, your logic is unassailable, and the other person is provably wrong, you

Here's the thing. Both with the religion argument and in general: even if you're right, your logic is unassailable, and the other person is provably wrong, you will still benefit from not assuming stupidity/broken thinking/etc, and instead seeking to understand the other person's position as thoroughly as possible. At one extreme, you may discover a flaw in your reasoning. Even if not, you may find that while not entirely sound, there are valuable aspects to the other person's point of view, which can make your world-view more nuanced. Or perhaps you will simply confirm your initial perspective... but even then, you're much more likely to inspire the other person to think on the subject than if you come in with the perspective that they're provably wrong (and perhaps a bit pitiable for it). By seeking to really understand someone, you inspire them to do the same for you.