If you look at how the word "hate" is used in both the OT and NT (based on the KJV / Strong's Concordance, of course), the context almost always suggests "rejection" rather than the emotional loathing we associate with the word today.
As humans, we must reject any evil that we have a weakness for. Whether its drink, drugs, lust, gossip, gluttony, etc, we need to be self aware enough to reject the people and environments that can bring us down. In our weakness, we are called to "hate evil." Also, in our humility we admit that our hatred is due to our own weakness, not due to others' issues.
Christ, on the other hand, being perfect, had the ability to go anywhere and be with anyone, without the concern for being "pulled down" into sin. And in being with "sinners" of any and every kind, He was and is able to bring hope and healing.
In our faith, we strive to be perfected and Christ-like, always loving and filled with light, without hate. Our hatred reveals our weaknesses, and in humility we confess that we are sinners. Hatred is a "necessary evil" in that its part of the process of striving towards perfect love.
EC