To the extent that there is a moral fabric among humanity, it is indeed fragile, and in this episode it is intentionally torn asunder by conquerors from outside humanity.
The fabric, the moral structure that makes it possible for Maple Streets to exist, requires a form of conformity, an agreement to share standards of behavior, to act and not act in certain ways. That conformity and uniformity has to coexist with the natural diversity within the species, the diversity of how we look, act, think, and behave. When technology fails on Maple Street, following a flash of light in the sky, the residents look for an explanation. A child provides it. Invaders from space have turned off the power, and have inserted a family, people who look “just like us” into Maple Street. As ludicrous as the suggestion seems , it is powerful, and the community starts looking for differences in each other, differences that would account for the loss of power. When the neighbors, acting like a mob, focus on Les Goodman, whose car started by itself, Charlie says, “Maybe under normal circumstances we could let it go by, but these aren’t normal circumstances.” What Charlies doesn’t get, is that it is precisely in abnormal circumstances where we need to be guided by principles of respect and autonomy, where we have to safeguard the freedom of expression, even when we find such expression odd or different. Les Goodman is no less a good man because he takes late night walks under the stars while his neighbors are asleep in bed.
As some of the residents of Maple Street appreciate on more than one occasion, they are themselves the monsters. The threat is inside. No bomb or invading army is required to destroy and conquer. This fact would be obvious to any intelligent alien, and it is one easily leveraged. It’s cold comfort that we’re unlikely to be discovered by such intelligent aliens. The conditions of our undoing are already in place, and we don’t need the manipulation of our technology from outside to stimulate our monstrous behavior.