Doing so would be leaving a flaming bag of dogsh*t on the doorstep of the incoming president, foreign policy. "Enjoy dealing with that whole ISIS situation now that I've angered a key ally in the region!"
Morally it's the right thing to do, but it would be bad form.
Sadly, this.
What I'm asking is why Turkey pushes that POV. I understand the rest of it.
It's complicated, but to summarize Turkey's biggest problem, domestically and in foreign policy, is Kurdish separatism. Although a different people and never subject to outright genocide like the Armenians, Turkish treatment of the Kurds has been at times horrific. Admission to wholesale slaughter and long-standing oppression of an ethnic minority that now has it's own nation again can only create moral and diplomatic support for an independent Kurdistan, the nightmare of most non-Kurd Turkish politicians.
Add to that the blind nationalism that many Turks follow, as reflected by Erdogan and his party being in power, and "the base" isn't about to admit such "obviously exaggerated" wrongdoing.