I don’t think I mean the ones removed by mods as they usually have a visible response to go along with it; because sometimes a post will indicate it has 5 responses or something but when I click on it I only see the pinned comment and nothing else. Is there a spam filter, or are those comments also moderated in private?
Same deal, yes. Not every comment receives a removal notice, mainly because if we did that, we'd just be contributing to comment count bloat. (Imagine a thread of ostensibly 100 comments, but 50 of them are mod removal warnings, heh.)
I always wished they could reset the comment counter, I see a post with 17 comments and I get excited the question was answered with some good follow up discussions just to have my hopes dashed when nothing is there.
But I am guessing there isn't a way to reset that
Edit: Just say someone mention a browser extention so I guess I will try that out.
Removed comments which don't have any replies to them don't show up as [Comment Removed] when you view the post so that will explain the majority of removed comments. If you're asking why moderators don't always reply to comments we remove, it's because the vast majority of removed comments are simple one line answers, jokes, speculation or other worthless comments which don't merit a removal reason.
If you want the comment count before clicking on the thread to reflect the number of actual visible comments, we have a browser extension just for this purpose!
Thank you for asking this. I have always wondered this myself.