Well technically it is 1 comment.. you're thinking more of replies.
I understand where you are coming from as a comment is usually considered a reply as well, but in terms of this message board each "post" is called a comment.
I agree with 3stripe. The first post is the discussion, the posts to the discussion are the comments on the discussion. So it should say "comments: 0" when no one has posted a reply. If "comments" was changed to "threads" or something then having the 1 would make sense. Thats how I see it.