[AnimalMuppet]

But who are they signaling to when they do this? Not the person they're arguing with. Not me, either, if I'm reading the conversation. To me, they're signaling "I refuse to actually consider anything the other person says. All I will do is argue and repeat my talking points. I might as well be a robot."

They're signaling to the people who pay them, and to the people who might hire them in the future, not to their readers. To their readers, they're kind of anti-signaling. I mean, are many people genuinely persuaded by whoever can yell the longest? (Because that's what they're doing. They always reply with something, and that something is never an indication that the other side might have even a shred of a point. But is anyone actually persuaded by some "brick wall" posting the last word at the end of some long back-and-forth?)

[clankyclanker]

I think you've got it: the point isn't persuasion, the point is exhaustion and disengagement. If you can keep shouting until the other side goes home, your opinions become more prevalent. You can then make your opinions so prevalent that other folks assume there's no point to engaging (voting? commenting?) because of how outnumbered contrary opinions are. At that point, your opinion has become reality. It relies on psychological tricks to subvert the one-voice-one-vote rule (c.f., State Street).

[vintermann]

Well, I'm sure some of them are signalling to people who pay them, too. But I think it goes well beyond people who are paid. They're telling the world "This is what it means to be a [republican/democrat/etc.], and if you aren't like that yourself, you're with the enemy!". It's like an ultimatum to commit.