Again, you could imagine them asserting one of the exemptions to the Act, but that would require them committing to a damaging position in paper. That is a major purpose of the exercise. The existence of that piece of paper would be a news story. (Man Claims Feds Out To Get Him On The Internet is not a news story.)
I don't think the feds are denying that they're out to get him. He's connected to the Wikileaks cable leak, the US government position is that this man is linked to what Hillary Clinton called, "ot just an attack on America's foreign policy interests ... it is an attack on the international community"[1].
yes but all those things can just been seen as politicians blustering. Politicians are very good at twisting words to say something while implying another thing. You get a bit of paper from the government saying "You there, you are not entitled to this", is worth way more.