This idea of forgiving in the context of “huge issues” such as the Holocaust is extremely controversial. Some will say that forgiving is not appropriate in this context for a number of reasons (The vast majority of people in the current generation were not in the Holocaust and so it is not their place to offer forgiving; some injustices are so grave as to eliminate the possibility of offering forgiving). Yet, there are people who are on record as offering their own forgiveness to the Nazis. The late Eva Mozes Kor, in the film Forgiving Dr. Mengele, is one example of this. People can forgive groups because when we forgive we do forgive people; groups are made up of people. Thus, if certain people so choose, they can forgive those who instituted Nazism or slavery, as two examples.
Also, the philosopher, Trudy Govier, makes the distinction among primary, secondary, and tertiary forgiving. Primary forgiving is when someone hurts you directly; secondary forgiving occurs when you are hurt because a loved one was hurt (a grandson, then, who is hurt by the death of a grandparent in the Holocaust, can forgive for his own sake, but not forgive on behalf of the grandparent); tertiary forgiving is when you forgive, for example, a public official who is guilty of corruption in another country. In this case, you are not hurt directly and, let us suppose for the sake of this example, none of your relatives were hurt directly. You feel badly, even resentful, and so tertiary forgiving is appropriate.
We need to remember that forgiving is a person’s own choice. Even if everyone else says that injustice X is too severe for anyone to offer forgiveness, we still might be surprised to see that someone steps up and decides to forgive despite popular opinion to the contrary.
For additional information, see Forgiveness Defined.