Don't forget the 2 ex pilots, who witnessed the "things" with their equipment and their own eyes, and don't forget one of the congressman who saw pictures taken by a pilot, pictures that he had to force access to, you know people who just (finally) want some decent answers to a decades old issue, but probably they are all just wacko's as well right?
This is one of the reasons they still get away with it, again, when there's nothing to it, drop the bloody secrecy and classification.
Behind the "national security is at risk " they can hide practically anything they like.
If they wish to hide that they have tech to detect those UFO's (tech adversaries might not yet have!) it probably is their right to do that ,no need to let Russia or China know what kind of high tech equipment you have, however there is absolutely no reason to keep hiding the existence of the "objects" themselves.
On top of that, if there were nothing to it, then why threaten whistle blowers or witnesses at all?, why stonewalling people of congress looking for answers? why not let them tell their "outrageuous" stories and let them hang themselves, what are they afraid of if it were truly all just BS?