We need to remind ourselves that the world - the so-called international community - have, with no exception, sat on its collective hand in every single genocide since the Armenian genocide by the Young Turks in 1915.
The most infamous cases:
Turkey's genocide of Christian Armenians (1915).
The nationalist Turks scapegoated the well-to-do and educated Armenians for the collapse of the Ottoman Empire, and proceeded to liquidate the Armenian population.
Forced death marches of Armenian communities towards the deserts near today's Kurdistan where the victims were expected to die in staggering numbers.
When the death rate proved less than expected, the Turk accelerated the destruction of their victims - by mass killings.
The only Western diplomat - based in Istanbul - who was protesting loudly was the American Ambassador.
In 1915, Britain was the world's superpower. Britain had other concerns: profits for the British firms.
The Holocaust (1933-45)
- nearly 5 million Jews, another 3 million Roma Gypsies, Poles, and other groups, as well as 27-28 million Russians (Western European governments with the exception of Holland and Poland) and USA were engaged - not opposed - Hitler and his men).
The Enlightened western civilization's responses, including Stalin's USSR, varied - from cooperation to appeasement, based on strategic calculations and self-interest.
USA - $$ lenders from Wall Street such as Mr "prestigious" JP Morgan (Oxford awarded him an honorary doctorate) and corporations (e.g., GE corporation) - were in bed with the Third Reich.
Britain - Hitler's men were seated at the top dinner table at the Palace dinners; British Military Intelligence (MI) was desperate to cooperate with the Nazi military intelligence, which had the best intelligence on USSR because Britain's feudal ruling class was paranoid about their property rights regime overthrown by the home-grown Communists, supported by the Soviet moles; anti-Semitism was also widely shared among the ruling institutions of Britain; the British Home Office gleefully issued rally permits to British Fascist (Black Shirts) marches - organized by a palace set the likes of Oswald Mosley; Prince of Wales was a known racist - just like today's Prince Philipps (the English Queen's husband).
Sweden deceived the world by claiming to be neutral, but was doing business with the Nazis. It was providing Hitler's Air Force with SAAB engines which were fitted in the powerful fighter-bombers.
USSR had a pact with Hitler, deceived the Eastern European anti-Nazi resistance groups such as the Polish Partisans. Heard of Warsaw Ghetto Uprisings
Indonesian genocide of the Chinese (CIA ) - 1964
US Gov. had a list of "communists" that wanted gone, and the Indonesian leaders had their own list.
(West) Pakistan's genocide of East Pakistani (Bengali) - (1971)
(Indira Gandhi's government used the Indian Armed Forces to put and end to the genocidal killing by West Pakistani army whose general ordered the troops "I want the land, not the people).
Khmer Rouge Genocide (1975-79)
(not yet declared a genocide by UN or lawyers, but commonly accepted as a genocide)
1/3 of Cambodia's population perished.
The backdrop was the carpet bombing of Cambodia by the United States as part of the military strategy to defeat the VietCom (N. Vietnam's Communist resistance), which received help from the Soviet Union.
The genocide was ended by the neighboring Vietnamese army.
Politically and financially, US (starting with Jimmy Carter), UK and China propped up the defeated Pol Pot regime, which regrouped and licked its wounds along Khmer-Thai border. The Thai military/gov provided logistical support, at the US's 'request'; Singapore led the whitewash of Pol Pot.
the genocidal policies were put in place since 1978 - Ngaga Min Operation - and the operational strategies have since evolved.
The United Nations have KNOWN all along what has been done to the Rohingya. It has gagged its staff about the truths. Only in the 38th year of persecution - 2016 - did the UN break the silence. That is after half the population of Rohingya have been driven out, killed, starved, or otherwise destroyed by Burma.
(Then there were Bosnia, South Sudan and other cases which I am less informed about).