Someone disagrees with you about something important – in person, someone you know well for other things. It's not that they are being imbeciles (I suspect we all can tell the difference as much as we pretend not to sometimes), they just disagree. Don't imagine, remember the last time this happened – how did you feel?
I remember being confused. I would explain a good reason to see it another way, they'd hear it, halfheartedly agree, and not be persuaded one bit. I think it's fair to say it was a failure of my empathy, but if you heard the actual conversation you wouldn't be surprised by that failure. It was baffling, and not just to me.
I've noticed this can happen when a principled person talks with someone who doesn't have those principles – but they never actually mention them. I think that's also the most charitable assumption.
It takes something else to get me heated. Someone wasting my time (someone spent more than an hour giving rapidly shifting Devil's Advocate arguments for something they didn't believe without ever mentioning it – it was quite a shock to figure that out afterwards) or someone encouraging others to be bad people, something like that. It happens, occasionally.
So you can imagine how confused I was by this Halloween story from Slate Star Codex about someone generating deliberately controversial and divisive statements. How strong is Scott Alexander's orthodoxy, that when he imagines something that could divide a community, that thing is disagreement?
A lot of orthodoxy is just random crap. I consider this a news and opinion blog, essentially – but you'd be forgiven for not being able to classify it as easily as me. The orthodoxy says "news and opinion" is a discussion where ideas of etiquette are a sideshow, for instance. I think that's wrong and dumb for maybe three obvious reasons and two less obvious reasons, but ultimately it doesn't matter. Disagree with the orthodoxy and it overwhelms you, you become an enemy to those who support it and an unwilling friend to those who hate it. This is the danger of orthodoxy, its principle characteristic.
That's why Scott Alexander imagines controversial statements to be so divisive, I think. He thinks a lot, runs a thinky website where lots of thinky thinkertons think a lot together. It's not hard, in that position, to look at a world where no one seems to think that much at all, and make the guess that, us thinkers, we should be pretty sure about a lot of things. Look at all the effort we poured into this! If we're wrong, we are honor-bound to change our mind, which makes people who disagree on things we're pretty sure about every more wrong! Now they have no honor!
It's not that different from the rise of Christian celestial orthodoxy (perhaps the most famously incorrect orthodoxy in history). Simply claiming the Earth could rotate around the Sun wasn't that controversial. But discarding all their work, for instance, their meticulous balancing of alternatives and reasons, saying there was a simple way to get an answer, that could get you in trouble. See, they'd done lots of big, important work thinking about all these things.
As much as Scott Alexander seems to value humility, it's possible he's under-cultivated the emotional and interpersonal elements of the virtue.