"fighting the enemy?"

...We still remember a proud city covered in smoke and ashes, a fire
across the Potomac, and passengers who spent their final moments on
Earth fighting the enemy. We still remember the men who rejoice in
every death, and Americans in uniform rising to duty. And we remember
the calling that came to us on that day and continues to this hour.

We will confront this mortal danger to all humanity. We will not tire
or rest until the war on terror is won...



(i didn't think they were "fighting the enemy." how does he mean that?)