In "The War of the Wall," what was the painter lady doing in town?

The painter lady has come to town ostensibly with the purpose of painting a mural. It is not until much later that her real objective is made apparent to the youths who resent her presence at "their wall."
From the children's point of view, the painter lady has no right to do anything to the neighborhood wall, where they play handball and the old people sit in the shade. The narrator is especially displeased to think that this woman may paint over their friend's name, which she has carved as a memorial to a soldier killed in Vietnam. Ironically, the children who criticize the painter for invading their territory and marking off spaces on the wall are surprised on Monday after school when they come to spray paint over the artist's work.
On this once-chipped wall, the artist has depicted people from the neighborhood, along with the faces of famous people such as Harriet Tubman, Martin Luther King, Malcolm X, "a handsome dude in a tuxedo seated at a piano" (perhaps Duke Ellington or Count Basie), and portraits of people from the neighborhood. These include the narrator's father and the narrator herself looking at a row of books. Her friend Lou spins a globe on the tip of his index finger as though it were a basketball. Suddenly, Lou drops the bag of black paint and rushes to the wall, running his fingers over the painted rainbow where Jimmy Lyons's name had been chiseled. Now the name is painted into this rainbow. The dedication of this beautiful mural reads as follows:

To the People of Taliaferro StreetI Dedicate this Wall of RespectPainted in Memory of My CousinJimmy Lyons