The abuse that he inflicted on the world and those around him came out of his own suffering, hatred, and delusion. As a kid, I didn't much like my parents either. My parents grew up in abusive and neglectful families, and that's what and how they learned to treat their families. There was no one to teach them love, patience, tolerance, forgiveness. And I didn't learn it from them either. But I discovered, studied, and converted to Buddhism, where those qualities are advocated and practiced. The very first teaching of Buddha after his enlightenment was the truth of suffering. We are all of us suffering. And knowledge of suffering is supposed to help us feel compassion for all other sentient beings. My parents are dead, but I still pray for them if they were reincarnated as another sentient being somewhere. I pray that they were reborn into a loving family and have easy access to an authentic teacher of compassion and wisdom. Don't nurture negative emotions of hatred and resentment. Hatred makes us stupid and increases our own suffering. May you have happiness and the causes and conditions of happiness.