Interesting little parable about a small town and the residents who suspect an alien invasion. "It could be any one of us...maybe even YOU."
People who got along, then a series of external events got everyone agitated so they started pointing the finger at their neighbor.
Sometimes the search for the monsters on Main Street makes monsters of the searchers. Sometimes "you're one of us, or you're NOT" is a real pain in the ass. Sometimes one side isn't "right" and the other side isn't "wrong"...it's just two fucking sides.
And in the episode, the people of the happy little town beat the living crap out of the people they think are on the "other side," and they feel better about themselves...for a while.
Funny how sometimes life imitates art...isn't it.