I feel sorry for your great grandfather. What kind of character was he? Had he overcome the trauma of that experience or talked also about the good things in life? 

Once the chain of service to the land and people is broken, the subversions of the previously dominant forces seem to foster such fanatical moods. The dynamics of the violent groups have certainly been studied and explained somewhere. I did not go into this in more detail, because it takes up the issue of finding the culprits. It is difficult to give examples where those affected by war have preserved their dignity and not where the atrocities are heating up people's minds again. 
Mordor is in each of us, but also in each is a sovereign who first wants to be awakened by the sovereignty of others. 

What country are you from?