The mechanism itself isn't necessarily a problem, it's the arbitrariness of it and the lack of accountability. Most people have some degree of accountability in their job. I think HN mods are an exception.
> whatever they did earlier
It would be impossible to audit whether this is being done judiciously or fairly without a page listing all such moderations, their context, etc.
> whatever they did earlier to reduce signal/noise ratio
I'd argue that moderation itself reduces the s/n ratio. If I notice a pattern where one user continually posts low quality comments, I'll be inclined to ignore or downvote that user. If the user got throttled, then it removes my ability to notice the pattern.
Similarly, if stories are re-titled (a common abuse of moderation) I may not realize I've already read the discussion or the linked content and read/click it again.
Worse yet, re-titling submissions often removes any clue about what made the submission interesting. Ironically the moderation practice of titling the HN submission with the article title introduces more click-baity titles into HN than would exist due to submitters' tactics.
No offense is intended by my feedback. I do think the moderators have a few pretty glaring blind spots and I am hoping that my feedback is well received.
I might have thought that too before working with a community this large, but the degree to which we're accountable is much more intense than anything I've experienced in a job before. When every misstep is met with instant outrage and hard pushback, you learn to adapt to feedback quickly.
People think we control HN, and to some extent we do, but we are controlled by HN to an even greater extent. This is maybe the most important thing for understanding how HN works. HN consists of a big system (the community) and a little system (the moderation) and the two interact via reciprocal feedback.
There's a third system too (the software), but I left it out for simplicity.