The above post is correct--Sue Bayliss does not feel that the Kellers are superior to her family in All My Sons. Sue does not really like the Kellers because she feels that they think they are better than all their neighbors. Sue, and many of the other neighbors, do not believe that Joe is innocent, and they are angry that Steve is serving time alone for a crime that Joe likely committed. Sue thinks that Joe is a braggart, and she is annoyed by his continually trying to win over the neighbors. Sue does not like when her husband Jim talks to the men in the Keller home because she thinks the Kellers give Jim the wrong ideas about life.
She doesn't think that they actually are. She resents Joe for being able to commit the crime and get away with it, and at the same time admires him. But she thinks that Chris sees himself as better than everyone when really he's just as aware of it as Joe -- hence her mention of "Phoney idealism."
She believes that Joe is guilty.