I pay pretty close attention. I browse with showdead on. Can you clarify what you mean by "don't show up at all"? Posts by banned users are dead as soon as they're posted, but I think you mean something else. Do you have a couple of examples of what you're talking about?

Mods will occasionally detach subthreads, and have even been known to remove them from a story.

As one might imagine, a subthread without even a story parent is basically inaccessible unless you know its precise ID.

Well it's not known to me. What makes you say that? We don't delete comments or posts like this, but if you know of specific cases we can certainly take a look.

You...do appreciate the difficulty in finding these instances if they weren't bookmarked at the time, right? Also, just how silly it is to have the alleged censors say "Oh, well, that's news to me--can you find examples of the things we memoryholed?"

It might help if you folks kept a public moderation log.

I don't think it's unfair to ask someone to back up a claim, especially when the dataset is publicly available through the API or (more conveniently) in BigQuery:

  SELECT count(*) FROM [bigquery-public-data:hacker_news.comments] 
  WHERE parent IS NULL;

Story and comment IDs are also simply incrementing integers. We're not making it easy on ourselves to hide this sort of thing!

Oh nifty. When did you all add that stuff to BigQuery? The Firebase API suggests that that dataset is going away in like a month.