@craigybourne: If they appear as a distinct character as well as being a species in the game then they can have both a character and a concept page. For example, the Pikachu in Pokemon Yellow and Smash Bros has a character page but we also have a Pikachu concept page for the generic species.
As dudeglove said, if you go to your profile page and click on 'Sub History' under the 'Wiki History' dropdown then you can see all your previous submissions. If you then click the edit number next to a denied submission it will tell you what the submission was and a moderator comment for why it was rejected. This is the submission in question and you're right that it was denied because we do not allow mods to have wiki pages. Team Fortress Classic is available as a standalone game on Steam which is why it has a page.
The wiki rules are decided by the staff so while you are free to discuss and make suggestions, ultimately it comes down to what they decide. If you have a question about a submission in the future then you can send a PM to the mods and we'll get back to you as soon as we can.