Why does this matter?
It matters because those who presented the news to us lied. It matters because the news sources scared us with the fear of hijacking and the fear of death unnecessarily. It matters because we felt terror and other raw emotions when, had we known the truth, we would instead have felt anger about being lied to.
Why would they do that?
They used fear to inhibit our ability to think. People in general do not think clearly when confronted with fear. A good many people panic instead or otherwise fail to consider alternative possibilities to the news that brings fear or terror.
So what happened as a result of the news of attacks on 9/11?
A public ready to receive a message of stopping that fear through attacks upon an enemy that never existed. And ready to scapegoat groups of people. And ready to go to war. Things the public was not ready to do on September 10, 2011.