The governments of Turkey hate talking about it in official terms largely because the rest of the world is kind of trying to hold the Republic of Turkey responsible for the crimes of the Ottoman Empire, despite the fact that Turkey as it is today was founded in 1922 after a fight against the post-WWI remnants of the Ottomans. Toppling over the sultanate and the caliphate were central to the founding mission. There's a cultural continuity to some extent, but but there is no political continuity. It's a separate country with a dramatically different set of values -- one that made a huge effort throughout the 20th century to adopt Western principles of a secular liberal democracy (though Erdogan is shitting all over that right now).

As with most things in this world, it unfortunately comes down to money. There are a lot of entities, particularly on the insurance front in France, who would raid Turkey's coffers in the blink of an eye the minute the government admits the Armenian genocide. Arguing over why Turkey is being held responsible for the crimes of the Ottoman Empire is a complicated international debate and it's not going to stop the multitudes of legal proceedings that will extract a shitload of money from the country. It's easier, though not ethical, to just deny the whole thing and keep the lawsuits at bay. Of course in the process, a lot of Armenians are undeservingly denied the justice and recognition they seek. It fucking sucks.

Now, by all means, lets commemorate the Armenian genocide and recognize the suffering those people went through. But System of a Down isn't helping the matter here. They hang signs up at their concerts that say shit like "No Dogs or Turks Allowed". It's ignorant. You don't get the Turks to be sympathetic to the Armenian cause by shitting on them and personally blaming them for crimes that their far removed ancestors have committed. All this hostility isn't helping. It's just making an already difficult positive resolution even more unlikely. A little less misdirected hatred and a little more putting yourself in the other side's shoes goes a long way in fixing any conflict.