Charlie shoots Les Goodman because he just sees a person come out of the dark and doesnt know who it is
Everyone starts to jump on Charlie when the lights in his house go back on and no one else's does
Everyone now starts to think the alien is Tommy because he warned them about them so his mother and him run
Monsters on Maple street is about how you don't always need a bomb or some other kind on weapon to destroy human kind sometimes if you take away necessities and throw them in the dark they'll all turn on each other. Once Tommy throws out the story about the aliens and the family not being real everyone jumps on each other out of their fear and suspensions. Once Les Goodman's car turns on and no one else's does everyone thinks its him and his family then they all start saying stuff about the person that they think would make them guilty. Charlie killed a man so quick out of fear and then they all jumped on him when the lights in his house turned back on and everyone thought he was the alien because he was so quick to judge and kill . Then everyone started to turn on Tommy because Charlie said he was the one who brought up the idea about aliens in the first place . The story shows that there doesn't have to be an actual monster there but the monster is inside of every human brain and mankind is it's own enemy.