I do not think that is the case. The last time I commented I logged out immediately after posting it, and when I am logged out, the comment is not visible. I see it when I’m logged in.
that is a "shadow" i dont know why anybody thinks its a good thing, but what happens is you see your posts and comments, but no one else does, so you think everything is fine, instead of abandoning the username and making another.
Ive wondered just how much storage space is "wasted" by perpetuating the illusion of participation when you are actually talking to thin air.
also comments that are downvoted heavily enough are greyed then removed from view.