It's important to note that this "we" is not a singular, unified being. It's a mixture of perspectives and opinions reflecting the town's collective knowledge and gossip about Emily Grierson, the story's protagonist.
This narrative technique, often called "collective narrator", allows the story to be told from a gossipy, ambiguous, and somewhat unreliable perspective. The narrator's judgments and opinions are shaped by the community's shared understanding and prejudices, contributing to the story's layers of mystery and social commentary.