Wikia does not serve any of the sites. The CNAME records in DNS direct the traffic to www.wikileaks.org.
The domain names were legally transfered to Wikileaks a long time ago, but for unknown reasons, Wikileaks never completed the technical aspects of the transfer. Wikia has made multiple requests to them to do so, with no result yet. Mr. Assange has indicated that he is very busy right now, which seems likely to be true, given recent news events.
To answer your question, when Wikileaks first launched they put out a press release calling themselves something like "the Wikipedia of secrets". We had no idea who they were, whether it was a scam or spam or who knows what, so some domain names were registered defensively. We contacted them immediately to see what was going on and they apologized for being careless with the Wikipedia name and everything was sorted right away with no problems... except for them actually concluding the technical aspects of the transfer.