I'm sorry you had to go through that. I understand it can be very traumatizing.
This has come up in my personal life many times too. I knew a woman that had been abused earlier in her life. She was once the victim and then turned into the bully, so to speak. In this situation, she justifies her behavior as a defense mechanism just as you were saying. She is so convinced of her perceptions that she is "never wrong" (it makes her feel safe and is extremely scary for her to let go of that), but many of her close friends and families see her as arrogant, combative, controlling, manipulative, and many other not so hot attributes. What is really sad is we witnessed her doing these things to her son. And the last I heard, now he is being really spiteful and mean to girls in his school. It's really hard to watch and feel so helpless. But I also think a lot of people have gone through similar traumas....generationally speaking.
The hardest part is, as we know, you can't change or control someone's behavior. At best you might be able to guide it if you're a person that can refrain from emotionally reacting to their outbursts, but that requires deep inner-work lest it seem patronizing to them. Those that are so deeply wounded need compassionate therapy that will really listen and understand in a way that feels connective to them- be it a unemotionally attached friend or professional. But like you said, they don't usually want therapy. I have seen some end up hitting what I call a 'spiritual brick wall'. That is, a traumatic life event that wakes them up. :(
If you are in a relationship with an emotionally, verbally or physically abusive person, the best way to get them to see that it's unacceptable behavior is to no longer be a part of that reality for them and make it clear as possible to them. You might have to just walk away. I think a lot of the times we try to help people by giving them love and physical presence, but if they are subconsciously interpreting that as enabling their behavior, then it's like telling them it's okay to act like that. If we react to it emotionally it also tends to feed their reality. It gives them something to fight for (to keep them safe) and it further justifies what they believe. But of course, if they are being physically violent, call the cops. It sends a louder message and keeps you and others safe. Even in non-violent situations, sometimes getting back-up or mediation from others helps a person behave better.
For my personal experiences, I've usually had to walk away. It was the most loving thing I could do for myself and them, not to mention those around me, like friends and family who also suffer when watching these things go on. It also takes strength to realize when you can't be the person to help them. Talk about developing muscles you never thought you had!
At the same time I've also tried to examine myself to see what I can do to become more emotionally stable so I don't once again end up with another person with similar issues. I realized my behavior was also inviting certain types into my life. I had to balance myself out, and still continue to do so. Repetitive relationship patterns are common if we don't try and learn from them and change ourselves. Ultimately, what I've learned from relationships like this is we have to do what is best/safest for us, and as compassionately as possible for those around us. If we keep the goal on a 'we' society it often helps us align our behavior easier.
Have you ever seen the movie Chocolat with Johnny Depp and Juliette Binoche? I thought the story line with the character Josephine was a great example of this topic. But really the whole movie is a great example and very character dynamic in building communities that are more acceptable in loving ways but also with firm boundaries for unacceptable behavior. It's one of my favorite movies.
What have your experiences been in situations like this?