As far as the US government, my guess is we're honoring our nondisclosure agreement with the foreign intelligence agencies that generated the information.
Sure, but can't someone have the sense to go back to such sources and re-negotiate, say that it's really really important to clear this up in the public because not only has US credibility been grossly and falsely impugned but it puts a dark shadow over the credibility of all western intel agencies? It is particularly important to explain the real facts in light of ongoing dangers with Iran, North Korea, etc. and the need for the publics of various nations to know that intel agencies do have some competence. OK, I suppose if it's the French who have been promised confidentiality, well they could not care less.....