User:Snogus

The GFDL, like the GPL, is not a contract; thus, the initial author of an article written under the GFDL is not bound by its terms. I can, therefore, revoke the license by giving notice to the licensee (Wikipedia, Wikimedia Commons, Wikimedia Foundation, etc.). Any language to the contrary in the GFDL is unenforceable. Therefore, until an intervening substantially-transformative edit occurs, all such submissions are subject to arbitrary revocation on mere notice to the publisher(s) by the original author, and upon revocation all publication must immediately cease.

Once a substantially-transformative edit occurs, copyright in the resulting work rests not with the original author but with the person doing the substantially-transformative edit, who is then obliged to relicense any further distribution under the terms of the license allowing the edit in the first place, and is prohibited from revoking that license by virtue of being the licensee on the original edit. Since such secondary licensees receive their licenses not from the original licensor, but from the licensee (whose rights have been terminated by the revocation), their licenses remain intact until they also receive actual notice of the revocation, and derivation licenses predicated on those licenses remain valid. It is probably possible for an original licensor to revoke these relicenses as well, but meeting the requirement for actual notice for termination is likely to be difficult.

All of this flows from the fact that a license that is not a contract cannot impose an obligation upon the licensor. It is also established law that a license cannot be made irrevocable without consideration, and there is no consideration received by the licensor for licenses granted under the GFDL (or GPL). There is simply no way to prohibit the original licensor (author) from revoking their grant of license, which is why you have to allow for author's prerogative to delete.

(All text text borrowed from User:Malber)

Fuck off Wikipedia.