How we cite our quotes:
"That's okay. […] You're a traitor to your own kind and not loyal to us." (8.98)
Ponyboy is speaking out of anger. He's offended that Cherry won't go to see Johnny on account of her loyalty to the memory of Bob. He seems mistrustful of anyone with mixed loyalties or inter-group relationships. Ultimately, Cherry's just trying to make sure nobody on either side gets hurt.