In this piece I believe Ilana Mercer misunderstands the Christian approach to forgiveness. It is true that God is just. However, Jesus bore the punishment for everyone else's sins--that's why Christians say "He died for our sins." (Someone used the analogy that God is a judge whose own child comes before him in court. Because He's just, he still levies the fine, but because He loves His child, He gives the child the money to pay the fine. Just so you're not confused, in this analogy the child is us, not Jesus.)
There are plenty of Biblical passages where Christians are instructed to forgive, regardless of the contrition or not of the trangressor. Also, one can forgive without "forgetting," in the sense that you could still not let a murderer babysit your kids, even though you forgave him for his previous crimes.
It's particularly interesting that Ilana (we know each other--I'm not using her first name because she's a woman) took this tack, because I think this is actually one of the major differences between Judaism and Christianity. In my view, God basically said to humans: "Okay, you want a list of necessary and sufficient conditions for moral behavior? Read Deuteronomy. You can't do it, huh? OK, so just love Me and love each other."