In other words, Bush was an idiot for believing the intelligence, but the intelligence was true.
Since Niger is a center for illicit uranium smuggling, does it not occur to anyone that smugglers might use fake documents?
What this article says is that, during the long months that Bush was taking it on the chin for his (true) charge of Iraqi interest in uranium, the Euro agencies that knew his charges to be true remained silent. The joke is that Iraq's interest in uranium wasn't even secret, and was not dependent on classified sources; Iraq's trade mission to Niger was public knowledge.
It is the active existence of Nigerienne smuggling rings that was not public knowledge, but whose existence was well known among the agencies who were paid to know such things.
Everyone it seems, except the CIA, who seemed to have needed the services of a self-aggrandizing liar, who managed to spend a week in the country without finding what everyone else seems to have already known. Illicit uranium mines were open for business.
What we've found in Niger, and in Iraq, is that the forgers often use inside information and official forms to make their forgeries more believable, so we've come across forgeries that have real information included in them and in some cases appear to have been done by someone who has seen the original, but the forger simply couldn't get their hands on the originals to sell.