Even if a person was not directly involved in the Holocaust, their family could have been forever altered by the Nazis killing family members. This can permanently change generations of a family. People should still be willing to forgive the Holocaust because it can help them let go of any resentment that they have towards the actions of the Nazis in the past. If people could not forgive atrocities that they were indirectly affected by, they will be more likely to harbor negative emotions in their own life.
By forgiving the Holocaust, they are taking control of their own life in response to the oppression of their heritage.