Assumptions for these thoughts: the human species is unalterably tribal (built on in-groups and out-groups in competition and conflict) and unalterably territorial (requiring owned spaces controlled by particular tribes).
Thought 1. When a group, no matter how large and powerful, loses its self-confidence --and that includes an assumption of specialness and superiority--what possible forces can prevent its eventual collapse?
Thought 2. When subaltern groups, who may be, on every measure, inferior to a dominant group, lose their fear of such a dominant group, what can prevent their eventually switching places?
Thought 3. A self-confident human group will react swiftly, without paralyzing self-doubt or even reflection, when challenged. This will take civilized and uncivilized, organized and spontaneous forms. Both are necessary.
Thought 4. If a group is so possessed by a high-mindedly un-selfish ethical complex that it is unwilling to do what is required for maintaining its status, even its survival, then it is doomed to humiliation and likely to extinction.
Thought 5. Consequently, if a group wishes to maintain its status (and power and wealth), then it must be cohesive enough and self-confident enough be able and willing to do very unpleasant things to people in competing and/or subaltern groups, both formally and informally.
These thoughts seem to me, IMHO, to describe how human groups actually function in the real world on planet Earth. It is not basically a matter of morality, but, as with things like eating, a matter of survival.