If F.O.W.L. somehow got evidence about the McDuck Family being the cause of Lunaris to complete his plans to invade Earth possibly with the Psychic Division if established, they could secretly show this to the world in hoping they would shun the McDuck Family. After all Scrooge built the Spear of Selene which Della stole after that, Della while being stranded on the moon, gave the plans of the rocket to Lunaris to start his invasion he’s been planning for years before Della’s arrival, and Louie after messing with the Space-Time Continuum, led to the moment of him running the company made horrible bad decisions on unleashing the Bombie and dropping a satellite in a failed attempt to stop the Bombie left Earth completely vulnerable for the invasion to accelerate. Even though by the end of the series Bradford Buzzard was the one who secretly told Della about the Spear of Selene, it was a well kept secret with no clear evidence.