You see people demanding apologies for American Slavery, Genocide of Native Americans, the Holocaust as well as many others. You really don’t see a whole lot of this behavior in regards to the Armenian Genocide. But Islam rejects Original Sin.
As a white person whom non-white individuals have on occasion held responsible for atrocities committed by my race in past centuries, I have felt not only bewildered but also victimized. I was at a very difficult place in my own life dealing with oppressive family and religious community, seeking asylum in mainstream society. Then to be accused of something someone of my skin colour did to someone of their skin colour generations ago—it was overwhelming. I personally had never done anything like it. I could not be responsible for more than my own behaviour in my own lifetime. I think I handled it well but the feelings went deep.
After experiencing the good feeling from the Catholic Church’s apology I understand that people want formal apologies. In a world where powerful white governments favour Caucasian individuals by default, perhaps this demand for apologies is an effort from the “other side” to rectify on-going racism, to bring attention to it, awareness. In Turkey, skin colour differences between Christian and Muslim were hardly as important as religious beliefs and politics. So why aren’t today’s Armenians demanding apologies? (I’m assuming the questioner is correct in the statement that not much of this is happening.)
Maybe belief in Original Sin plays a role in these demands, as suggested. The Bible declares that “sins shall be visited unto the third and fourth generation.” See:
King James Version (KJV)
7 Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear the guilty; visiting the iniquity of the fathers upon the children, and upon the children’s children, unto the third and to the fourth generation.
At this link http://www.history.com/topics/armenian-genocide is the story of the Armenian Genocide. From about 1890 to 1915 Muslims tried ridding Turkey of Christianity.