Coverup
It's probably on purpose, done with the full blessings of whoever is in charge of information warfare. So when an enterprising journo thinks "Hey! I'll check wikileaks to see if there's something from the MoD", all the nice bits are hidden behind a mountain of dross. Information burka, so to speak. Steganography, nearly - it's there, but you can't get at it.
Big Brother, 'cause you're trying to watch him but can't take it all in...