@Pippy I struggle to come up with an exact fit.
I think "The Old Man in the Cave", with its paramilitary demagogue and the deaths his "leadership" causes, is a decent candidate.
Or "The Monsters Are Due on Maple Street", where some aliens are able to spur a societal breakdown in a small community with a few cheap tricks.
I always come back to "A Stop at Willoughby", where a man's refuge in a realm of false nostalgia leads leads to his death. Malignant nostalgia does seem to plague us.
@Marc_T_Benedict one of the main ones I thought of was “The Monsters Are Due on Maple Street”, there’s another I forget the name of the episode where it’s a nuclear test site set up as a town.
@Marc_T_Benedict I couldn’t either.