The ladies' attitude toward the Mrunas (a black tribe living in Africa) is that they live "backwards" and that they need to be taught how to live properly and reaise their children properly. This is why the women are glad that Christian missionaries are visiting this tribe, and the women feel they should put their support behind this.
However, these same women, who gather together for the purpose of supporting the mission of their church, will not lift a finger to help the poor blacks of their own town. They are able to talk about hwo great it is that someone else is willing to help the poor, backward black people of another country, but when it actually comes to doing something productive, the women would rather sit around and sip tea and gossip.
It is also ironic because the women feel they are part of a better society than the Mrunas. From the description in the book, it's clear that the Mrunas live a rather simple, natural life--and the tribe works together to make this happen. The women who are supposedly "better" live in a town that convicts obviously innocent black men and gossips about them behind their backs.