How does miss strangeworth secretly warn the the people of the possible evil in The Possibility of Evil?

In "The Possibility of Evil," Miss Strangeworth secretly warns the townspeople of potential evils by anonymously sending letters that highlight their flaws and shortcomings. She believes that by exposing these perceived moral failings, she is protecting her community from corruption. However, her actions reveal her own misguided sense of superiority and contribute to the very evil she seeks to prevent, ultimately leading to her downfall when the townspeople retaliate against her.