I agree with you on all points but one: even G-d cannot forgive transgressions against another human being, only the victim can. That is why murder is so unforgivable - because that is literally true. He can and does forgive for transgressions against His law. Keep in mind that I am Jewish, and thus bring my faith’s P.O.V. to this question. On Yom Kippur, our Day of Atonement, we are required to ask forgiveness of those we have wronged in the past year, and show some to those who have wronged us...because if we are asking G-d to forgive us for sins against Him, we have to take the first step.
As for K.G., kudos to him for letting go of the hatred that would be natural in these circumstances for anyone. I’m not sure that I could do that. Note that I believe that he can forgive this animal for the emotional harm that he, himself, suffered.
He is not an animal. He is a man, a child of God, whom God loves very much, who has sinned horrifically, and whom God earnestly wants to repent so he can be forgiven and eventually spend eternity with him in heaven. I don't presume to tell a Jew what his faith teaches, but as a Christian, that is what our faith teaches us.
Calling him an animal is simply an excuse not to have to face the prospect of forgiving him.
And before you say "if it was your sister....", well, don't go there because... Let's just say KG isn't the only one who has had to tread this path. I'm glad he did.
And that’s the fundamental difference between Christianity and Judiasm.
Christians believe all transgressions are against God primarily and against other people only secondarily. Secondly Christians believe since God through Jesus has already paid the price for all the sins and earned forgiveness for all who believe in him, that any debts between individuals are also settled by him at the same time.