A person becomes angry as a reaction to the perception that something has happened to them that they didn't seem to choose.
The perception of things happening outside of your will, is victimhood, and usually entails some 'other' source or person that 'causes' the situation. And since they seemed to choose it 'for you', you see yourself as being unfairly or unjustly treated.
Then you believe that your anger is justified because you see yourself as 'innocent', i.e. it's not you that's wrong, but the other.
Whenever it is the other that is wrong, i.e. you are angry at them for any reason, believing they have done something, you ARE in victimhood.
Now, it may not seem like victimhood, because we may usually think of victimhood as when you feel afraid or you've been attacked and are hurt or whatever. But if you're in anger, you definitely are experiencing and perceiving yourself as a victim, or as having been victimized.
Anger comes out of the hurt. Anger comes out of the victimization.
You may not realize that being angry is being a victim, because the anger turns into victimization or outward attack/retaliation, which makes it feel like you are 'empowered' or 'rising up against' the oppressor, which gives you a false sense of being justified in making THEM a victim, which conceals the fact that if you are angry, you DO perceive yourself as a victim and are playing a victim role.
This absolutely REQUIRES that you, cooperatively, willingly, and freely, have actually chosen to go along with the perception of seeing the situatuation in such a way, that you look like you've been victimized. It requires your own mind to look at the role you're playing in the situation, and to conclude that you didn't ask for this. this is of course grossly mistaken because you cannot be an unwilling victim. I know that is incredibly controversial and maybe hard to accept, but the mind actually USES situations to position you as victimizable and attacked, because it has motives that run much deeper than just this situation (such as the death wish, or the desire to be unconscious).
So as the Course says, "anger is NEVER justified".
It's never justified because nothing ever happens to you against your will. And you MUST have chosen to perceive yourself as being in a 'victim dynamic' in order for you to then experience the reaction to that perception, which manifests as anger or righteousness.
So yes. If you are angry and upset in any way, you MUST be believing you are a victim, and probably you are blaming the other person, and probably you are not admitting honestly the part that you play in this.
It requires tremendous HONESTY to be able to realize and admit not only that you are angry because YOU CHOOSE TO BE, and not only that you're angry because YOU VICTIMIZED YOURSELF through your false perception, but also to be honest enough to admit that IF you do not choose to see yourself in this 'role' or 'relationship' to 'other', then you CANNOT experience yourself as a victim and therefore cannot be angry.
I myself did not realize that being angry was being a victim, until Jesus pointed this out. And if you see yourself as victimized, your anger WILL turn into victimization quite quickly. Then you will retaliate. That's what anger is, a retaliation (reaction) against a perceived mis-treatment. But you can never be mis-treated. If you see yourself mis-treated, you are mistaken in your perception and you are unaware of the power of your own mind.