Empathy doesn't have to come direct experience as you have just shown. Neither is empathy one dimensional. From my perspective i applaud him recognising someone bringing peace whixh is what i assume he has done
I assume Duffy is acknowledging his part in bringing peace to his country. Fair enough, he was a key part of the journey. I doubt he is celebrating his time as killer. Might be wrong but I would need to hear that from him. May peace continue.