Eliminates incompetence, and those who break the laws."
Some people out there seem to think that out of sight really is out of mind. The extremist cousin of the Ninja Editor, this is the type of person that goes to great lengths to remove all evidence of a particular online activity in the hopes that the Internet will forget about it if it's no longer available. If someone criticizes their work, they respond by just simply replacing or flat out deleting it wholesale. If a forum allows editing posts, they'll gladly blank it out. If not, they'll demand the administrators cover up this embarrassment.
Of course, once they delete every trace of their embarrassment they can get in reach of, they will then proceed to deny its existence. They never wrote that incendiary racist propaganda thinly disguised as a Death Note fanfic where Light kills off the entire African continent. What the hell are you talking about? That post where they said Hitler was right? A forgery by the other members of the forum to ruin their good name.
People don't just try to hide their own actions, either. Just as frequent are the cases where a Message Board administrator attempts this on other people. For example, let's say a political debate ends up with the administrator's side flat out losing. This admin could choose to then delete the entire thread, every reference to the thread they can find, ban all the most vocal users that won the debate, and constantly police the rest of the members to ensure they never, ever talk about it again. This is an excellent way to drive away forum users. No one wants some Small Name, Big Ego type with an agenda policing their every word.
Either way, whether or not the person that partakes in this behavior is actually hiding something truly damaging is irrelevant (in fact, most of these deletions themselves weigh a lot worse on them than whatever was posted in the first place). What matters is that they think that all they have to do in order to mask something on the internet is to Delete Friggin' Everything.
The name refers specifically to the novel Nineteen Eighty-Four, where one major aspect of the society was a total willingness to rewrite the past ("We have always been at war with Eastasia.").