Mrs. Merriweather refers to the people who live up north (the Northerners) as hypocrites. Remember, hypocrites are people who say one thing and do the opposite.
Mrs. Merriweather calls the Northerners hypocrites because of the way they treat the Negroes. Mrs. Merriweather says that "people up there set ‘em free, but you don’t see ’em settin‘ at the table with ’em. At least we don’t have the deceit to say to ‘em yes you’re as good as we are but stay away from us" (Chapter 24). She says that people up north have set the Negroes free, but won't sit at the table with them. The Northerners says that the Negroes are equal, but don't act that way. Therefore, they are hypocritical.
Mrs. Merriweather seems to think what the Southerners do is better: to say that the Negroes are inferior to the white people and to treat them that way.
When Aunt Alexandra has the Missionary Society meeting at the house, Scout decides to go. She ends up sitting with Mrs. Merriweather and she hears how Mrs. Merriweather talks about Helen Robinson. Scout is confused as to why Helen shouldn't be able to work to take care of her kids, but Mrs. Merriweather is convinced that it would not be okay for her to be around the white people in town. She calls the Northerners hypocrites for being behind the freeing of slaves, yet they don't want anything to do with them either.
"Hypocrites, Mrs. Perkins, born hypocrites," Mrs. Merriweather was saying. "At least we don't have that sin on our shoulders down here. People up there set 'em free, but you don't see 'em sittin' at the table with 'em. At least we don't have the deceit to say to 'em yes you're as good as we are but stay from us. Down here we just say you live your way and we'll live ours. I think that woman, that Mrs. Roosevelt's lost her mind coming down to Birmingham and tryin' to sit with 'em. If I were the Mayor of Birmingham I'd-"
It is amazing to me that Mrs. Merriweather is talking bad about the northerners all the while she is one of the worst hypocrites in town. She thinks that it is all right for the south to still be okay with slavery because we didn't free them, and the north were the hypocrites because they freed them, but didn't want to sit at the same table as them.