The way I interpret is that a system at an IP the Wikitruth people believe to belong to David Gerard made a large download (probably a scraping, possibly a series of Mediawiki XML downloads via the Special:Export feature) of their wiki. They thought they'd make a wry joke out of it.
Bizarrely, some of the numbskulls at Wikipedia Review have interpreted the sign on that site mentioning David, along with Orlowski's comment that he believes it to be run by "Skip...[a] 30-year-old Silicon Valley IT professional...along with a dozen other Wikipedia administrators", to mean that David is involved, and constructed a strange conspiracy theory that has David Gerard, and by extension the entire Wikipedia Cabal, running WikiTruth as a kind of humor site.