Anger is an emotion, it's not a behavior.
In a mentally/emotionally healthy person, anger usually occurs when one has been hurt, betrayed, or otherwise violated in some way by another.
The way a person expresses anger is under their own control.
Healthy expression of anger can only occur when a person is not being oppressed and controlled by others.
Anger expression is not the same as aggressive or threatening behavior; they're two different things.
Expression of anger looks like an expression of POWER to those who use it that way themselves, and also sometimes to those who still have trauma issues from past experiences.
When a person is being oppressed by another, or by others, they are often not "allowed" to express their feeling of anger, because anger expression is a PRIVILEGE of STATUS that only those who are in positions of power are free to display.
Literally, because those in such groups equate anger expressions with POWER DISPLAYS.
Therefore, those who see themselves as higher status are the only ones who get to display and express anger, even in a polite way.
~Many who come from dysfunctional groups/families/communities think that anger and aggressive behavior are the same thing.
That's like saying joy and jumping into the air like Snoopy are the same thing, or that fear and screaming at the top of one's lungs like a yodeling banshee are the same thing. Emotion is emotion, and behavior is behavior; one influences the other, but they are two separate things.
One's emotions only directly dictate one's behavior and actions IF one has emotional or mental illness that has not been recovered from or treated, or if one has not been guided in separating their emotions from their behaviors during childhood.
PTSD triggers are not the same as emotions; diving under a table when one sees a weapon, or their ex, is a PTSD triggered behavior, for example, "fight, flight, or freeze". However untreated PTSD can and does cause serious problems both for the sufferer and for those around them, like other disorders do.
While most healthy people don't completely separate their emotions from their behavior, and occasionally let their feelings "run away with them", they do take responsibility for it, and they can control their actions to a relatively high degree, including the way in which they express their feelings of anger.