If you read the sticky you would know pruned posts don't take away from post counts. It just deletes the topic (Without removing post counts). Someone turned it off. And posts in the garbage count aren't supposed to count anyway. It's just that the function to turn post count off here is either non-existent in this forum or no one can find it >.>.
Having a pruning system in the garbage can allows you to at least keep your post count - unless someone deletes it first. Regardless, pruning > deleting for moderators and for you guys since you get to keep your posts.
The only reason it was deleted was because of the 1000 post contest.