I'd rather have it obvious as a uniformed employee clearly doing it in the open, than some shady act of "corporate espionage"
Should they have found a more poised person yes, but it's better than someone in a hoodie and sunglasses sitting near the gate trying not to look suspicious! Then you have an actual scandal instead of a made up one.
DL is I'm sure just trying to build a case that there is no way that QR can possibly have enough load factor to maintain the flight if they cared about profits.
Has DL started some rather petty routes against AS, yes, but they did it with a CR7 or 737 and the routes were maybe 1000 miles instead of a 7500 mile flight out of sheer spite on a 777/380