Earlier quoted context omitted.
I used Power Delete Suite to remove all comments from all public and private subs. They all came back today. So I re-deleted them again. I suspect it's more likely the site didn't process the deletions properly, rather than maliciously bringing them back, or as you suggest, that they were private. Edit: It's possible that the deletion only worked on public posts, after all, it seems?
Absolutely this. I highly doubt Reddit would want to fuck this up at this point for seemingly minimal gain. Much more likely that a 10x increase in deletions caused some pipeline to collapse somewhere.
But would the current upset userbase even believe reddit if they came out and said "our deletes arent working right now. please try again later."