The root cause of self-hate is the lack of unconditional acceptance by parents in babyhood. If we look deeply into our self-hate, we can understand the root cause through insight. Then awareness (true self) revives and can heal our wounded inner child and release our ego with pleasure. Only if we attain that insight, we can transform self-hate to unconditional self-love by the energy of compassion. Unconditional self-love, or self-acceptance is the foundation of unconditional love to others. Mindfulness and concentration are the means to attain that insight.
Thay said, "So, in psychotherapy, low self-esteem is sickness. And the healing is trying to promote the self, to bring it a little higher. That’s not a fundamental way. But we have to see that high self-esteem is also a kind of sickness. Low self-esteem brings a lot of suffering but high self-esteem also brings a lot of suffering. You can make many people suffer and you suffer also. And also a complex of equality is not healthy." (For more details, refer to: http://compassion5151.blogspot.jp/2015/11/impermanence_25.html)