Why did Steve tell ponyboy that he wasn't going to show up for the rumble?

Steve told Ponyboy he wasn't going to show up for the rumble because he was feeling disillusioned and tired of the ongoing violence between the Greasers and the Socs. He believed that fighting wouldn't solve their problems and wanted to avoid the cycle of retaliation and conflict. Steve's decision reflects a growing sense of weariness with the gang lifestyle and the desire for something more meaningful.