They have that... I believe it's scientology.org.
Wikipedia is not the place for it. If you read the scientology related articles, they do a very good job of presenting both sides of the story. The reason scientology is banned is because they have a LONG history of deleting all negative viewpoints, and even whole articles on things like David Miscavage, The Fishman Affadavit, OT3, Tommy Davis, and Xenu, just to name a few.
The reason that they were banned was not to disallow them their viewpoint, but rather that they were constantly disallowing others' viewpoints.