The story starts out in what appears to be an idyllic setting: a tree-lined street in 1950's America, filled with happy families and friendly neighbours. But things are not always as they seem...
Later on, brooding over the continuing blackout, Charlie remarks to his wife that it's like a return to the dark ages. This is truer than he knows although not for the reason he thinks. The real darkness is caused by the descent of the street's denizens into attitudes and actions based on fear and superstition, letting these things outweigh their rationality and sense of community. This results in the transformation of neighbours and friends into possible- maybe even probable-suspects. The Maple St. residents start to regard each other distrustfully, putting the worst possible spin on the motives of The Other; they grant no benefit of the doubt, and reject the need for evidence or proof. They might as well be demanding trial by ordeal for suspected witches.
The Monsters Are Due On Maple Street takes a rather dim view of human nature and, while I don't believe by any means that this is the only possible human response to an inexplicable, fear-inducing situation, it's certainly a very possible one. As anyone who is on Twitter could attest to, there are any number of people who in the face of a crisis are- like Charlie- ready to shout, "Look, look I swear to you...it isn't me...but I do know who it is...I swear to you, I do know who it is. I know who the monster is here. I know who it is that doesn't belong. I swear to you I know." This has never and will never end well.