Right.
I have to assume that you are saying that America had to suffer the WTC attacks in order to not expose these same entities!
You assume 100% incorrectly. Would you care to try again? On second thought, don't bother.
How many times do I have to tell you this before it sinks in?
Just as soon as you start making sense, that's when.
Stopping an attack (presuming you have managed to gather enough information in advance to know it's coming) doesn't require giving away the particulars of what you knew, when, and how.
Showing your evidence to the public does.