Why do you equate "genuinely appealing to some feature of human psychology" with benevolence? Killing a rival is genuinely appealing to some feature of human psychology, so is "to crush your enemies, to see them driven before you, and to hear the lamentations of their women".
I don't expect the joy of crushing one's enemies to be stable under reflection. If you really know deep down that your enemies are just humans like you with a slightly different set of genes who grew up in a different culture, crushing them probably seems less like a good idea, on the grounds that the badness of the subjective experience of suffering being crushed shouldn't depend on whether that experience gets implemented in your own skull or somewhere else (e.g., your enemy's skull). At the same time, however, the underlying features of human psychology...