I agree it is rough. Semantically, I would say that forgiveness doesn't lose its power. Rather it can take more power to forgive someone when it becomes apparent that they are not remorseful and will likely not change.
However if we do not forgive and instead perpetuate stereotypes and biases (of any kind) we are ultimately injuring ourselves and those that come after us.
I'm not saying it is easy. I'm not saying it would be simple for me if someone murdered my family member.
In this case forgiving doesn't mean the withholding of justice from the guilty he should definitely be prosecuted. Instead it means the personal healing and liberation the victims can obtain from embracing kindness and understanding instead of hate and revenge.