I'm having a little trouble with the forgiveness, too. I think the key is that the forgiveness ISN'T tolerance.
One of my all-time heroes is Corrie ten Boom. She and her family hid Jews during WWII and were a part of the Dutch underground. Her story is told in "The Hiding Place" and I fully recommend it and any other book by Tante Corrie (Tante means Aunt...and it's fun to say!) After speaking in a church one day, she looked up to see a former Nazi officer who had been one of the guards at one of the concentration camps she had been in, Ravensbruuk, I believe. He was holding his hand out to hers. She recognized him...she didn't want to shake his hand and prayed very quickly. God gave her the strength to shake the hand of her former captor. She had this to say about forgiveness....
Forgiveness is an act of the will, and the will can function regardless of the temperature of the heart. Corrie Ten Boom (1892 - 1983)