Playing devil's advocate here. Perhaps former seminarians can enlighten me.
1. From the cross, Jesus said, "Father forgive them they know not what they do."
We are told to commit a mortal sin it must be serious, we must know it's serious and we must want to do it anyway. The Jєωs didn't know or believe He was the Redeemer, yet Jesus indicates they are still guilty and in need of forgiveness.
2. Jesus, Second Person of the Trinity asked for their forgiveness, would the Father have refused Him?
This was all after the Jєωs accepted His blood on themselves and their children.