Anger is a function of grief and is something we encounter when we see or experience injustice. It is self protective and is often a necessary part of healing, especially following Spiritual Abuse. Anger is a stage and function of grieving, too. Don't believe otherwise. Learn how to move through anger and master it so that it doesn't master you.
Forgiveness and the Path of Denial (Denying Anger)
Self Deception in Forgiveness: The Path of Bitterness as a Cycle of Blame (Expressing anger in indirect and unhealthy ways)