How does Scout come to the realization that Mayella Ewell is the loneliest person in the world?

From the book: "White people wouldn't have anything to do with her because she lived among pigs; Negroes wouldn't have anything to do with her because she was white. She couldn't live like Mr. Dolphus Raymond, who preferred the company of Negroes, because she didn't own a riverbank and she wasn't from a fine old family. Nobody said, "That's just their way," about the Ewells. Maycomb gave them Christmas baskets, welfare money, and the back of its hand. Tom Robinson was probably the only person who was ever decent to her.""

As the details filter out during the trial, Scout realizes just what kind of a life Mayella leads. Alone and abandoned, she reaches out the only way she knows how. In this case it will cost the life of a gentle man, a mockingbird. Scout sees Mayella unable to handle respect. Mayella's life is filled with abuse from the town and unspeakable acts from her father. Mayella has absolutely nobody.