They didn't establish that the events didn't happen (they did) only that the scenes were invented.
The Clinton administration DID inform Pakistan that it would be sending cruise missiles into Afghanistan AND Pakistan DID warn Al Qaeda of the attack so that they could evacuate the camp. That is not up for debate, that's history. It happened. The scene, with Madeline Albright making arguments as to why they warned Pakistan and the other dialog was invented but it's a matter of detail not a matter of rewriting history.