What does the quote "its just as much Maycomb County as missionary teas" mean?

Atticus says this to Aunt Alexandra when Jem is so upset after Tom Robinson is declared guilty.  Aunt Alexandra thinks the children shouldn't have been allowed to go to the trial, but Atticus justifies it by saying, "This is their home...they might as well learn to cope with it" (Chapter 22).  He believes the children should be exposed to the reality of their hometown, the good and the bad.  He goes on to emphasize that the injustice of the trial is as much a part of Maycomb as the good parts, as exemplified by things such as missionary teas in Aunt Alexandra's eyes, even though subliminal attitudes of racism are ironically well entrenched there too.