Anger is often healthy and relevant. I think hate is probably frozen or festering anger, which may happen when you are extremely angry about something you cannot do anything about.
For most of my life I have not understood hate, but has come to me twice, once when someone I loved was falsely accused of a crime, and it almost ruined his life, secondly when an indifferent health system cost my best friend his life. I could not do anything in either case, and the hatred is still there though I work on letting it go.