Because the Senators basically were giving approval and saying it was "personal choice." They all knew. It wasn't a denial by the CIA like the MKUltra program where they lied about stopping it. They admit that it has merit and that it will continue.
While I see where the kids are making mistakes and shining a light on things, the kids are pawns. It's the reporters that they're being used by over and over that are the problem. Unless that part of it is exposed, the kids will just be called victims of manipulation and the perpetrators will lurk in the shadows.
These documents definitely make me look back at every journalist detained as a (spy) in a new light.