The important word should be "was". If you try to remove it from the past, by arguing semantics or by any other means, you make it stick into the present. A past genocide would be much easier to live with than a permanently unsettled question of genocide or war event or war atrocity or paranoid fantasy of everybody else conspiring to sully a history they actually don't even care that much about as if they had nothing better to do.
The thing is, history is full of ugly things and arguing them creates a much stronger link between the uglyness and the one arguing than ancestry could ever do.
It seems there are sometimes slightly cruel things you just have to do, if there is a war going on ... was that your point?
https://en.wikipedia.org/wiki/Armenian_Genocide