Works for me, but yes I can see how irritating it could be if 90% of those posts are unavalible to you. I do agree though that the "my LFS has a mantis" is a bit much, unless its an uber rare species. If someone is looking and posts a want thread I would PM if my LFS shipped and had one, but not just a "hey look what the LFS got in".
As others have already said mantis lovers come in here, and a post in the Buy/Sell would probably just end up with a bunch of BS "kill it", "can I have it to feed my trigger" etc. Also we are a fairly small group unlike Reef Fish or SPS/LPS etc. If they were to post for sale in the SPS or LPS forums then the meat of the forum would be lost. IMO we don't have that problem here because of it being a small nich group.