"First of all, you cannot have ex pos facto law. The definition made in 1948 does not, of course, apply, to what happened before that time. You cannot blame the Turkish Republic for the actions of the Ottoman government in the same way that one does not blame the government of Russia for the large scale Russian massacres of Jews during the 19th century.
Secondly, the Ottoman government never had the intention to massacre anyone; there is absolutely no evidence at all that the intention was to destroy the Armenian population. There were large scale Armenian revolts in eastern Anatolia, attacking the Ottoman army, and in particular cutting its supply lines, including an open revolt in Van which slaughtered most of the Turkish population. The intention of the deportations was to end the attacks which the Armenians were making on the Ottoman army that was fighting against a Russian invasion that had been invited by the Armenians, centered at Van, to get them out of the way while the fighting was going on. Muslims and Jews were deported in the same way.
Thirdly, it is very doubtful that more than 300,000 Armenians died in the Ottoman Empire during and after World War I, at the same time that almost 4 million Muslims died as the result of massacre and starvation. The Hamidiye guard employed under Abdulhamid II was established to restore order and security in the eastern provinces after violent Armenian revolts had killed thousands of Turks; the only government-sponsored intentional killing that took place at this time, aside of course from military activities, was the Brtitish naval blockade of the Ottoman Empire during and after World War I, which was intended to starve the Ottoman population to death and caused the deaths of 40 percent of the population, Muslim and Christian alike."