In any case, I think most of us have felt what the writer here feels, about HN or some other forum. It's hard to know how much of it is internal to us & how much of it is the forum. I mean, as we hang out someplace, it becomes old to us. Cliches become trite. Insights become banal. Patterns become annoyance triggers. All stuff that tends to show up in these "sick of this" endpoints.
What made me think of it here is the first "bad argument:"
"Arguments that reduce to a disagreement about semantics"
While I agree that this is a bad argument, it's a pretty common one anytime anything abstract is discussed. Even professional philosophers exchanging letters, debating on podcasts or publishing in journals succumb to semantics disturbingly often.
To me, I might get drawn into some topic/debate and eventually conclude that it's just boring semantics. At that point, the whole thing annoys me whenever it comes up. This was how I "got sick of philosophy" at Uni.
I don't know if it matters to the individual, but to forum designers it might have opposite implications. If it's the forum that changes for the worse, a cultural defence is the right approach. If it's the person who changes, then the solution is an evolving forum. It's also hard to get feedback on this. I can't imagine many forums ever avoid this sort of sentiment from arising.
..no conclusion.