Perhaps the most vulnerable minorities to exploitation and extermination are 'milch cow minorities', hated groups who exist merely in order to be exploited, but who are themselves relatively economically successful.
This I get from the work of Thomas Sowell, who gives many historical and modern examples - he calls them 'middle men' - and cites the Jews in medieval Europe, Chinese in Malaysia, Indians in Uganda and others.
Such middling minorities benefit the community in economic terms, which is presumably why they are tolerated; yet their success compared to the average makes them the subject of envy and resentment, while their political weakness makes them vulnerable to the ruling class.
Typically, they are subject to arbitrary 'justice' in that for a minority citizen to be accused of a crime by a majority member is to be guilty - so they live at the whim of the majority, and must be submissive as a condition of survival.
Often, the ruling class can - for some reason or just on whim - stoke-up and direct mass anger at middle minorities; and they are attacked, expelled, exterminated.
On average the community ends up worse-off, because they have killed the milch cow; nonetheless this has often happened in history and is happening now in Africa and the Middle East (for example), because some people can benefit in the short term from the opportunities for looting and the rest of it.
But all modern societies, at this stage of their development, are in economic terms milch cow exploiters: because all modern states are Leftist and depend almost entirely upon a shrinking minority of productive native men.
(The unique factor here is that the modern milch cow minority has been artifically created by the inverse mechanism of privileging all other groups to make a coalition united only by their economic interest in exploiting the milch cow. Such is the long-term logic of democracy.)
What are modern Leftist ideologies (socialism, liberalism, feminism, multiculturalism) but rationalizations for milch cow exploitation?
Any examples of continued economic success among any of the milch cow minority make the whole group subject to envy and resentment - this hatred then justifies further ratcheting of exploitation under guise of egalitarianism.
Such arrangements are brittle, unstable.
To attack (in some fashion) the productive minority upon whom your medium-term standard of living depends would seem to be self-destructive, is indeed destructive in the long term, yet it often has happened, is happening.
(After all, modern-style mass migration from third to first world is very obviously socially destructive, yet it proceeds apace.)
Because few people are long-termist - fewer than used to be.
The secular Western ruling elites, in particular, have become extremely short-termist, with a time horizon of a couple of years max. They are also personally more selfish, dishonest and exploitative than for many decades.
Destructive things may happen when they benefit key individuals who have the ability to make them happen.
It makes little sense for a family to starve, mutilate, or slaughter and eat their milch cow: but nonetheless this can, does, and quite likely will happen.