Background information on myself, I am from Turkey studying at USA and I have went to school in Turkey that taught the entire incident as a genocide, and taught it as not a genocide. This whole topic is being taught extensively in Turkey starting elementary school. I wasn't born yesterday and I have a noticeable knowledge about how the world works, how the politics works and how history works, so I am not going to take sides here saying it is a genocide or it is not a genocide and only convey what I've been taught so far.
After Ottoman Empire has grown collectively, there were multiple nations habited in its land, Greeks, Uzbeks etc and of course Armenians. Here are couple of facts to consider.
1) Armenians had been a part of the Ottoman Empire since day 1, they had very high up ranks in Ottoman Empire and up until late 1800s(conveniently when Greeks started an uprising and gained their own land) they fought in every single Ottoman Empire war wholeheartedly.
2) Russia had a politics to reach the Meditterenean. They bloomed late, didn't have as powerful of an economy as there was and their economy wasn't developed enough. What is the fastest way to get there? Thorough eastern turkey to meditterenean.
3) So when French revolution started, the thoughts of freedom and nationality spread out and nations that weren't Turks decided it was their time to get their own land which is somewhat justifyable. Uprisings and disturbances started to occur and the Ottoman Empire is known to use force to stop them. The more they used it, the more it became more efficient and the uprisings became more violent.
The way it is taught in Turkey, now when WWI broke out, Russia started whispering into Armenians ears. Armenians started uprising, and went on a killing spree in Eastern Turkey. They attacked bunch of local towns in Eastern Turkey and killed bunch of innocent Turks who were nothing but hospitable. Sounds familiar? It is because it is the exact same version from Armenians sides. Now here's what I think, did Armenians decided to just started burning down houses? Probably not. Did Ottoman Empire just make a reckless decision and implemented "Let's wipe out Armenians out of this world" Probably not either. So as far as I'm concerned, I believe due to the lack of information and proof in Ottoman Empire back in 1900s we are probably missing some information what REALLY happened. Now why Turkey is constantly denying all this could be summarized as follows.
1) Why hasn't this been mentioned before? Why Armenian Genocide became such a hot topic starting late 1990s conveniently when nations started to separate again? (cue Kosovo)
2) Any leader that plans on running again for president will never ever admit it is a genocide. It is signing his own death sentence.
3) Armenians were like Ottoman Empire's own. When they betreayed Ottoman Empire, they were hurt but then again why would a nation known with their hospitapility decide to eradicate their own nation
4) Turkey is not Ottoman Empire. If you even read a 1 page essay on how Republic of Turkey has been created, you will see the monarch regime and the family line of Ottoman Empire has been cut and exiled when Republic of Turkey has been declared. Some argue that the massacre is a Genocide due to the definition of UN, when the 'genocide' happen Ottoman Empire's army had Greek, Uzbek, Macedonian, Mongol, Armenian, Syrian etc soldiers. If Turkey, a country that was a part of the Ottoman Empire, is responsible so is every other nation that had a soldier in Ottoman Empire's army.
5) For some reason history somewhat became a subdivision of politics. Some European countries use Armenian Genocide to demand lands from Turkey. US government refuses to. If, in fact, the evidence is irrefutable, why hasn't there been a conclusion already. Or is the world waiting until Middle East settles down and Turkey is not required as a reliable base for many military forces?
6) Whoever has been informed of Turkey's casualties, 400-700k based off of recorders, responds with, "wait i had no idea this was the case" Meaning some evidence has been hid and moved around. If Turkey was to stood up first and said it is Turkish People genocide, would the situation be reversed completely?
7) Records show Ottoman officials have only ordered deportation, not to a desert but simply out of Ottoman Empire borders. A short study of history will show there were lots of military uprisings against Ottoman government, due to the lack of expansion and loss of lands. Thousands of Ottoman military officials have been sentenced.
On an unrelated note, no, it is not as the same as Native Americans. Please no one say, "it is not your issue so you don't know what you're talking about.' It is also not the same as Hitler trying to eradicate one nation.
TL;DR I said a bunch of things about what is the controversies about Armenian issue for Turkish people, hopefully it is helpful!