The naming makes zero sense even when it makes sense - a director's cut of a movie is stuff originally filmed/produced but edited out in the editor's cut. In games, they are adding content, so it doesn't equate to cutting stuff out. Even symbolically, who's the 'director' and who's the 'editor'? The producer/project lead may hold the project to tighter limits than preferred, but how often is that lead not the director also?
I think in real terms, they are "rushed to make a prearranged release deadline version" and "actually finished properly as intended version", or more aptly the "crap version" and the "proper version", but I doubt any publisher will be brave enough to label the release version "Crap version - wait for the proper release!"