How do you explain forgiveness by unbelievers? Does it exist, and in what capacity vs. Christian forgiveness? Mormons and Jehovah's claim to believe in it, and I remember a Jewish apologist saying that Christianity was unnecessary because Judaism teaches forgiveness and that Jews can forgive just as much as Christians. To what extent do they actually succeed at doing it from your understanding?
What you describe is just natural forgiveness. It may be quite real. Even animals, pets, can forgive you. That's quite different from God's forgiveness, which is heavenly.
What about Eva Kor? From what I understand, she is not a Christian (a non-religious jew, supposedly) and forgave nazis who tormented her during the holocaust.
A very charitable act by this lady doesn't mean that God forgive them. For God to forgive a person must accept that they have done wrong, repent and ask for forgiveness