Anger would be a natural response to someone sinning. A sin will ultimately cause injustice to another person or to yourself. I know that I get "angry with myself" when I sin. Jesus takes that sin away when I confess, and I can let go of the anger.
Anger when injustices are made, is a healthy anger that can propel us into action to eleviate the injustice.
Being angry without being able to change the behavior, is to me a waste of energy. Uncontrolled anger, is generally not constructive, and would cause more sin to happen.
Blessings upon our understanding.