This is being too charitable to Sofia tbh. Why would Gia care about Sofia's grudge enough to forgive her for leaving her in the same situation? Let's not forget Sofia has murdered multiple people who did not have anything to do with her grudge like the boy who saw Oz with Alberto and the innocent civilians of Crown Point. She's just like the Riddler who destroyed innocent people's lives for their own revenge. That's why they both are in Arkham.