All emotions are just emotions. It is silly to get so hung up own which ones are secondary emotions and which are primary emotions. People are more than the sum or extremity of their emotions. People are more than just that.
If someone can truly claim to have answers, they do not lie in the emotions they do or do not have. The answers lie in what you have done and what you do and what you will do in the future.
If someone feels a terrible, negative emotion, but chooses to act in accordance with the morals and ethics that guide that person's life, then it matters very little what emotion was felt at the time.
As a woman with PTSD, there have been many moments in my life in which I felt great emotional pain in many forms. I have looked out and seen another person, and have found peace in feeling compassion, caring, and nurturing in the same moment as my pain. There is something greater than the emotions, and that is the soul, the mind, and choice. It exists and it directs me to feel a higher path even when I am angry, scared, or hurt. I am able to feel that while I'm here, there is the opportunity to make the world better for me and/or someone else. Dr. Viktor Frankl, a concentration camp survivor of WWII, also felt that to have the power to remove suffering from another gives meaning to one's life and one's joys and sorrows. He was also a psychiatrist, who studied and argued with Freud and Adler, having been mentored by the later. He believed in the Will to Meaning as higher and more universal than the Will to Power/Pleasure that Freud believed drove everyone most heavily.
The Will to Anger is neither of these, and the preoccupation with anger belies a lack of awareness that there is much more at work in human motivation than emotion. That notion predates Freud and is over 100 years out of date in simplicity.
Survivor, remember that people don't "care what you know if they don't know that you care." Joy and Peace inside are important. But people can go on being very loving, even feeling high levels of outrage and anger. It is good to find one's bliss internally, the point of grace. But that doesn't release the anger permanently. It will find it's rightful place.
Did Jesus feel joy and peace when he died? Did the leaders of the Civil Rights Movement feel peace when they were being threatened and beaten? I didn't feel joy and peace when I ran into the road to save my dog that got brushed by a car to save its life. I felt fear, love, and primitive feelings of "not wanting to sit and watch my dog die." People have differing definitions of "anger" and "peace" which cannot be the same for any two individuals, any more than God or Self could be. There will always be similarities, but no two inner worlds are the same, not even in identical twins.
Chimps who see another chimp about to be killed will heroically jump down and save it, even at their own peril. Researchers are not clear about if the chimp is aware that it is saving the other at its own peril. But it is clear that even animals do not want to watch other animals die and to sit idle.
I think it is a lot of pointless speculation to care so much what an abuser is feeling in his emotions. Who cares unless that is the subject of your Ph.D? What matters is what people do on purpose, how it affects others, and what we can do about it. Human responsibility and freedom do not care what that person felt that day.
If someone's goal is life is to rid oneself of a particular human emotion, say anger, than the other emotions will also be affected. St. Augustine said that only one capable of great evil could also be capable of great good, by choice. Since his time, researchers have noted that some people experience a more narrow range of emotions and do neither much good or bad to others lacking effect upon the world overall. Others are very dynamic and whatever they do, and leave a great ripple effect, good or bad. It is important that people be aware of who they truly are, for that does go out into the world. But it is not necessary to rid oneself of anger in order to do that.
Finding out what feeds one's anger that has set up shop in the human heart is, as you have said, vital to knowing who one is. One should take the time to work at neutralizing it, and using all the energy of the person to reach goals, do good, and feel proud of one's contributions to society is all that is necessary to create a healthy balance in the world. If one feels the need to expel the anger and replace it with peace, so be it. However, Justmehere's example is one of sublimation, which does a similar thing. Sublimation is the process by which a person takes deeply rooted negative feelings that are natural and shared by moral people and channels them for a higher good for the world. This does something inside the person like alchemy. That anger is not the same now it was put to good use.
If we didn't have anger, we wouldn't have MADD Mothers Against Drunk Drivers and people would still be legally allowed to text while driving. Negative emotions motivate people to change the world. If we all smoked pot enough to claim we were no longer angry, we would not do anything to improve the world. We don't need more hippies. We need more angry and loving mothers and fathers, who make the world more accountable and just for the future children.