(Some species developed submission instincts to get along with each other, pro-survival-wise. For various reasons, eldrae developed MURDER TO DEATH THE INTERLOPER THAT DARED TRESPASS UPON YOUR SELFNESS instincts instead.
Which made civilization rather harder to attain, but possibly more civilized - in the "we have learned to walk carefully, not presume, and reach out with gentle hands" sense - once attained. Or so it is argued.)