Miss Maudi isn't going because she thinks it is morbid or gruesome to watch a poor devil on trial for his life. It reminded her of a Roman carnival.
It did look like a Roman carnival because everyone came in with wagons and animals and there wasn't a place to tie down another animal. The whole town showed up for the event. The courthouse square was covered with picnic parties. Everyone was eating and drinking and having a good time. The Negroes sat quietly in another part of the square. There was a group of old men called the Idler's Club who usually sat in the square watching the events of the court. Atticus said they knew as much law as the Chief Justice just by observing what was going on. When they were given the signal, they all rushed into the courthouse. The Negroes sat in another part of the courthouse, away from the white folks.