They are basically bigots. They complain that their "help" are "complaining" about what is happening to Tom Robinson. Mrs. Merriweather is stereotypical of many Southern women in Maycomb who see black people as children or even sub-human. They do represent a low point in the novel. These ladies are not only self-righteous; they hide behind the guise of "Christian values" to de-humanize people who are black. These women are interested in helping people in Africa while they oppress Black’s in their own community. They also criticize Atticus while they eat his food.
"Gertrude, I tell you there's nothing more distracting than a sulky darky. Their mouths go down to here. Just ruins your day to have one of 'em in your kitchen. You know what I said to my Sophy, Gertrude? I said, 'Sophy,' I said, 'you were simply not being a Christian today. Jesus Christ never went around grumbling and complaining,' and you know, it did her good. She took her eyes off that floor and said, "Nome, Miz Merriweather, Jesus never went around grumblin'.' I tell you, Gertrude, you never ought to let an opportunity go by to witness for the Lord."