@roger,
Right you are! As a self proclaimed impertinent - I mean
important person, I will give my idea.
I have seen this sort of thing a few times and I think what happens is a person registers, makes posts which are against the TOS here and so they are removed. However, the number of posts register doesn't have a way to go in reverse so the count remains.
A way to test out this theory would be to take a Spammer (there are several in the late hours). Their posts get axed. Bookmark their profile and look at it in a day or so. If the count remains and the posts do not, then you have the answer.