Hate, anger, fear, are effects. They are caused.
This is one of the greatest truths of our time, and intrinsic to understanding the people around us. Thank you for putting it so simply. Invariably caused by pain deep inside, and a hurting ego often from years before. Knowing it makes it easier to deal with people, even, especially their hurtful side knowing that they are hurt. You can’t always mitigate it with love, but often you can, and always it is worth the effort.