'Is 'power' over 'others' evil?' First you must define 'power' & 'evil...?
'To be self-serving'? Everything is Self-serving
'Greater good of community...Why?' Because it serves your (self-serving) interests.
'To gain 'power' from others' misery? If you want to feed off negative energy, so be it. You reap what you sow.
What Socrates, Plato & aristotle did for the general public was to devise simplistic methods, based on ontological (Psych & philo) expertise, of Control and Conditioning - In order that the 'ruling' class revolved around a societal-platform of Willing (conditioned), subservient drones.
Have a Lovely Day
Well he is not so far off but matters like these are never openly debated because society just doesn't allow it...expected.
What if I say to you that "Evil" is a necessary condition to keep the world going, to keep the "Bios" busy and alert, to keep consciousness engaged eh? How would you answer with some degree of intellectual honesty?
Am I endorsing evil? NO! But I think that I do understand the Moral landscape dance better now that I am older...somethings are necessary even if we abhorred them! Just like death.
Just, if you don't mind - Wish to focus, momentarily, on that One line of yours.
'Why do we have such a hard time accepting our own egocentricity?'
Because 'Our' intent is to 'Dissolve' 'Our' egocentricity - Not 'Allow' it to Dominate 'Our' true, Free, Self/selves.
EGO is the Greatest enemy of Source-Consciousness-alignment