Good and evil are labels we as humans put on things so these terms are intricately woven into the psyche by indoctrination and varies from person to person, cultures, and religious indoctrination.
We also stuff what we consider as evil about ourselves into our psychological 'shadow' of denial and project it on to those that have a psychological hook we can hang it on. Learning to come to terms with one's own shadow leads to many benefits and withdrawal of one's projections and a different viewpoint not clouded with all kinds of prejudice.