In Chapter 2, Miss Caroline tries to read the students a cute story about some cats who are a lot like human beings. They have long conversations and they make clothes and they order food from a drugstore. I think that the kids do not like this story because it is too far from their actual life experiences.
The clue to this is that Scout mentions the kids' clothes and how they've been working since they were little during her discussion of the story. She is basically saying that these kids have tough lives and are not really interested in this kind of cute story that has so little of a connection to anything real.