There's a huge billboard on the corner of 49th Street and 7th Avenue in Manhattan calling for peace and reconciliation between Armenia and Turkey. Paid for by the Turks because they realize they've got a hell of a public relations problem. Things were going fine for about a century but now everyone's very upset about all those poor Armenians killed off by the moribund Ottoman Empire in its final years.
Too bad for the Turks they're brown and Muslim, because otherwise no one would care.
If there is one unassailable myth in modern Western countries, it's that genocide is universally frowned upon. Clearly this is a trait only granted to the civilized white people, as ISIS and the Indonesian Army are still pretty fond of exterminating Yazidi and Timorese respectively, but everyone from the frothing Texas conservative to the mochaccino sucking Williamsburg liberal is supposed to agree that trying to murder a whole tribe is a bad thing.
And to their credit, they do - but only on a case by case basis. Your typical sullen majority cracker couldn't care less about dead brown people - probably thinks they're all Muzzies anyway and good riddance - and even the most bleeding heart in Berkeley would be hard pressed if asked about the Herero. The Germans may have practiced for Auschwitz and Dachau in Namibia but you won't see Witbooi's List sweeping the Oscars anytime soon.
The popularity of the Armenian Genocide demonstrates the only two ways you can get people to care about the extirpation of a minority tribe: the victims are white Christians and they have many surviving relatives in a safe place far from the bloodshed. It's why Holocaust movies are their own genre and it's why anyone in America even knows about this one instance of Ottoman mass murder.
It's certainly not the bloodiest crime of the Ottomans. That distinction belongs probably to Yemen, who were a basket case before the Brits even showed up thanks to the Sultans. But you won't get the middle-class middle-brows of the US and UK to care about some long dead Arabs. They're just not relateable as victims.
That's why the same Brits who love to get on their high horse about the evils of genocide (Turkey) and fascism (Russia) have few if any words for their own colonial victims. Their murder of hundreds of thousands of Kikuyu - well after they and all the other world powers had agreed to knock off the genocide - gets barely any mention. Same with the Malays and Tibetans and just read this old post already. You can fill a lot of mass graves as long as it's not with white folks, just ask the Antebellum South or their legions of modern apologists.
But even if you don't have the misfortune to be black or brown in this world, you really need that vocal lobby in the safe countries to get anyone to care about your genocided tribe. Cyrpiot Greeks, despite being at this very moment under Turkish occupation, don't get anywhere near the attention of the Armenians because 1) they can't muster the same PR and 2) the ECB has spent the past six years telling all the US and UK yokels that Greeks are to blame for everything wrong with the world economy. So despite having an even more pressing grievance than modern Armenians, all those non-Turks in Cyprus are just shit out of luck.
Turkey has the bad luck of their ancestors killing loads of the ancestors of identifiably white and Christian folks with expat communities in the First World. If not for those specific circumstances, #ArmenianGenocide would not be trending on Twitter, nor would you even know Armenia exists. It may be a kind of justice, getting recognition for one of the many horrors perpetuated by an empire on a minority tribe in history, but it's a very perfunctory justice. A tacit admission of "This is the best we can get." Because if there were real justice for all these past genocides then flying the Stars and Bars in the US would be a capital offense and England would be on fire. Forever.