What is hypocritical about the concern of the ladies of the missionary circle have for the mrunas?

This whole section of "To Kill a Mockingbird" explores very nicely and poignantly the theme of hypocrisy as the ladies of the Missionary Circle are concerned for the oppressed black people half way across the world but are not concerned and do not even acknowledge the oppression of the black people in their own town of Maycomb.