What is the message Mrs. Merriweather is sending the ladies of the Missionary Society in Harper Lee's To Kill a Mockingbird?

In Chapter 24 of To Kill a Mockingbird, Harper Lee uses Mrs. Grace Merriweather's message about the African tribe called the Mrunas and forgiving the Negroes to express the hypocrisy that dominates Maycomb.

At one of Aunt Alexandra's meetings of the Missionary Society, Mrs. Merriweather explains the state and culture of the Mrunas. According to her, men of the tribe "put the women out in huts" when they have gotten too old, and children are dreadfully mistreated and riddled with parasites and disease. She feels it is her Christian duty to persuade others to go out to the Mrunas since currently only J. Grimes Everett has had the courage to "go near 'em." Unbeknownst to her, Mrs. Merriweather actually gives a description of the tribe's society that directly parallels Southern society:

The poverty ... the darkness ... the immorality--nobody but J. Grimes Everett knows. (Ch. 24)

In the middle of her description to Scout of the spiritual darkness of the tribe, Mrs. Merriweather breaks off to start talking about the "cooks and field hands" in Maycomb, meaning the African Americans or what Maycomb citizens would refer to as the Negroes. According to Mrs. Merriweather, the Negroes have been "grumbling" ever since Tom Robinson lost the trial, and according to Mrs. Merriweather, the best course of action is to "forgive and forget" the Negroes, especially to "forgive and "forget" Tom Robinson's wife, Helen Robinson, for having had such a sinful husband. Mrs. Merriweather argues that, if Maycomb's citizens "forgive and forget" Robinson's actions, they will teach Mrs. Robinson Christian ways, and perhaps she'll be able to teach her children Christian ways.

But, of course, what Mrs. Merriweather is overlooking is the fact that there is nothing to "forgive and forget" since all evidence points to Robinson's innocence. She is further overlooking the fact that the African Americans of the county are acting out because they see exactly how much the verdict of the trial was based on racism. Therefore, likewise, the Christianly Mrs. Merriweather is also acting and thinking based on racism, which shows the amount of hypocrisy that is deeply rooted in Maycomb county and in the South in general.