Whenever a Christian considers whether they should forgive someone of something, the answer could not be simpler: yes. No matter the person or group, no matter the offense. The answer is always yes.
Teaching in scripture is clear. Christ followers are to forgive everyone, of everything, right now. How else are we to receive words like, "Forgive as the Lord forgave you"? (Colossians 3:13) God had Jesus die on the cross as forgiveness for the whole world, whether they receive it or not. Whether they own their wrong or not.
What does this stir in you? What and who does it bring to mind? If you are like most of us, you may intellectually agree with the idea of being forgiving, while emotionally ducking its demands with someone, excusing yourself because what they did (or are doing) is just too much.
However, mature Christians forgive everyone. They forgive everything. When the need for forgiving arises in their life, it becomes a top personal priority. They know that there is nothing more anti-Christ than unforgiveness.
Mature Christians can honestly pray the words that Jesus taught us to in Luke 11:4 - "Forgive us our sins, for we also forgive everyone who sins against us."
To be clear, I don't believe the struggle to forgive is a sign of immaturity. It is often a struggle. But the mature embrace this struggle, learn from it, and let it do it's good work of maturing them to look a little bit more like Christ.
The immature do not. They justify, argue, and rationalize. Admittedly, their arguments are sound by earthbound standards. But we are called to the Kingdom. Embrace your teacher, whatever it takes, called Forgiving.