On the Internet, there is no place to go drink and talk quietly with the reasonable people about complex subjects while the inpatient people, polarized to one side of a multifaceted issue, try to out shout each other. So when I don't say something in a thread that has degenerated, nobody sees me leave.
I do try to leave something in such threads. But nobody is reading them for carefully considered takes on the issue.
I respectfully disagree, but that's because I'm in a couple of communities that are very, very cleverly moderated and have very rigid curation guidelines that the mods are careful about.
You still get people trying to shout at each other, but they usually do so from a distance, and not within the community. I'm perfectly happy with that.
HN has moderation (flags/upvotes etc.) but a much less rigid set of curation guidelines (see "Six Degrees of Hacker News"). This results in a much wider set of "well I think HN should be X", and therefore more meta-arguments about the different Xs rather than staying on topic, whatever "topic" means to each individual.
On reflection, you are right. I am actually in an online community that does do this, and even has a Metatalk section intended for talking about such things. I suppose I was engaging in hyperbole, born out of a sense of frustration. Thank you for pointing that out, and if you want to tell me (perhaps privately) about your communities, I'd be interested.
I do try to leave something in such threads. But nobody is reading them for carefully considered takes on the issue.