They may very well have done all those tests, now they were doing a final test.
Is the author saying that the US helicopters were sent out without ever having a real fire test, and that the first real test with real people was done on the battlefield?
There is a video. The video was clearly done for a purpose. Not hard to imagine testing the equipment extensively with live fire, then on the aircraft, then, finally, after they'd come out with this amazing armor and glass, take a video to show to pilots who might otherwise be skeptical of claims made by their not-so-trusted government flunkies. Now the pilots know, and knowing is half the battle.