The left word "genocide" doesn't mean what its English cognate means.
A people can be subject to "genocide" even while losing no man and growing faster than all surrounding peoples. The left word "genocide" preserves merely the "bad thing" part of the English, but doesn't refer to remotely the same concept.
Rather left "genocide" refers not to attributes of the event but to characteristics of the perpetrator.
Usually Jews commit "genocide", sometimes Americans do. It has nothing to do with the number of people dying or why they died.
Thus there has been a "Palestinian genocide", which happened during a time of an Arab population explosion (no pun intended), and there is currently a "genocide" happening in Iraq where Americans occasionally kill a terrorist trying to blow up Shi'ite worshippers.
The left "genocide" has inherently racist qualities. Since the correct usage of the word depends on the perpetrator of the act, the perpetrator's suitability is measured according to certain standards. The absolute number of victims or whether it approaches a relative percentage close to 100% of a certain group has nothing to do with it.
Thus a "genocide" is not when Jordanian terrorists kill 20,000 Iraqis. It's also not attempted "genocide" when Arab nationalists try to eradicate Israel and throw the Jews in the sea (i.e. kill them all).
Instead the definition relies on qualities of the perpetrator. And the qualities that have emerged are ethnic definitions.
There appears to be a level system which defines when an act becomes "genocide". If the perpetrator's race or nationality is "lower" (the KKK can explain what "lower" means in this regard) than the race or nationality (or perceived nationality) of the object the act becomes "genocide".
Thus an Arab attempt to kill all Jews is not attempted "genocide" but a Jewish attempt to kill a few thousand terrorists is (because the terrorists are Arabs).
And thus the US killing a few thousand terrorists is "genocide" but Sunni Arabs killing 20,000 Shi'ite Arabs is not.
The word is also seldom used to describe the events in Sudan, where Arabs are slaughtering blacks. If it is used then it is in most cases by people who would not use it for the killing of a thousand people. (In Sudan hundreds of thousands were killed in the last few years.)
The level system goes, from low to high, from Jews via Anglo-Saxons via blacks and Shi'ite Arabs to Sunni Arabs and further to Aryans^H^H^H^H^H^HIranians.
No Sunni Arab "genocide" against lower peoples exists (Kurds are lower people, but George Bush did not END a "genocide" in Iraq, he STARTED one). When Iran threatens Israel, it is not an attempt at "genocide". When blacks slaughter each other under UN supervision things become a bit more difficult (blacks are in the middle). In that case "genocide" is used only when referring to the event in isolation, never when comparing it to "genocides" caused by Jews or Anglo-Saxons.
Note: Anglo-Saxons were higher up on the scale before they allied with Jews and these days Iraqis. Iraqis are, in that system, the lowest Arabs.
Also note that the two words go back to the same root word *genocide in the English language and still meant the same thing 60 years ago.