the turkish population supported and encouraged and even took part in killing this christians mainly armenians.

Especially in the east in effected towns and villages where the Armenians defected to Russian side during the war and raided villages and towns, people did support it for revenge, which eventually got out of hand in the hand. While Armenians were under Russian influence (as both are Orthodox Christians), Ottoman Empire was under German influence just before and during the war years (as they were allies) where high ranking German military officers were working as military consultants alongside Ottoman officers in Anatolia when they were building the Berlin-Baghdad railway. That's only natural. The early American settlers supported the annihilation of Indian tribes during their expansion towards West, imagine how they would react if a minority ethnic group would help the Russians invade America during an America-Russia war. It wasn't only Turks, but Kurds who fought along the Ottoman armies also fought and killed Armenians while Kurds who uprose against the Ottoman state also became Ottoman targets even though they were Muslims.

But the conflict between ethnic groups began in 19th century as the wave of nationalization hit the empire as it did the rest of Europe. Not only Armenians and Balkan states, but even Palestinians and Arabs in Palestine and Arabia uprose against the Empire (see Lawrence of Arabia) in a hope to gain independence, which they never got.