I think the theme of the story is mankind is it's own enemy. I believe it is this theme because throughout the story the residents began to accuse each other after how Tommy told them the monsters sent down a family of four.After Tommy told them about the monsters the residents began to start becoming a mob because the residents of maple street began to believe that one family might not be what they seem to be. At the end of the story the residents fully turned on each other and started harming each other and the aliens talk about the pattern happening.
It's It's TOMMY
No It is NOT ME
ATTACK EACH OTHER WAIT IT IS CHARLIES NO LES NO STEVE anyway ATTACK.