The debate will likely continue ad infinitum: are narcissists the result of their own free will choices over time resulting in their becoming dangerous and evil, or are they victims of genetics and/or bad circumstances? The debate will likely never conclude because there will always be a large number of people who refuse to acknowledge the reality of volitional human evil.
The position I've taken on this blog is that malignant narcissists provide ample proof that they've chosen to be what they are. Did they set out to become the menace that they are to all their relationships and society in general? No, of course not. Evil people don't see themselves as evil. They've turned the world upside down so they are righteous and all those who oppose their will are the evil ones.
The debate on whether or not malignant narcissists create themselves or are victims of circumstance and genetics doesn't have to be settled in order to deal with the problem of what they are today in the here and now. We can completely lay aside origins when deciding the best course for ourselves and loved ones going forward.
Consider the rabid dog.
Let's say you are suddenly confronted by a rabid dog. You are staring into the eyes of a beast who has malignant intent toward you. You know beyond all doubt that this dog will bite you given half a chance...and you know that bite will likely kill you.
At that moment does it really matter HOW or WHEN the dog became rabid?
Would understanding all the circumstances and reasons for how the dog became rabid help you in that moment of confrontation?
Obviously not. What the dog is at this moment is all you must enter into your calculations on how to proceed.
Even though the dog became rabid because he himself was the victim of a poisonous bite doesn't matter one tiny bit to your situation of being directly imperiled by the rabidness of that dog. It is completely irrelevant as to the WHYS and HOWS ... what is relevant and useful is how to protect yourself from the rabid beast right now.
I hope my point is clear. No matter how you believe the narcissist in your life became malignant doesn't change how you must deal with that person. After you are safe from the narcissist's predations you'll have more of the luxury to examine the whys and hows of what kind of person they are. Hopefully you won't even then spend too much time on that line of inquiry. Acceptance of the reality of who they are today is much more useful than expending your precious energies on how they got to today in the shape they are in. Because any so-called understanding won't change what they are now.
I know there are individuals who justify their endless theorizing on the etiology of NPD on the basis that this will help us to someday cure NPD. I think this is hopeless naivete. Genetics, circumstances, social forces always provide only partial, at best, explanations. There have always been too many people with fewer advantages, harsher circumstances, more horrible family lives who manage to overcome these things to become decent people in order to explain away the ones who don't. Another aspect of naivete that these saviors of narcissists demonstrate is their reliance on psychology for answers. This should make us laugh ourselves hysterical. Psychology is itself nearly hopelessly clueless on the nuts and bolts of NPD.
I realize that the analogy of the rabid dog is imperfect. Malignant narcissists are not insane, mad, out of their minds. The correlation is the desperate malignant intent toward you and all others; the clear and present danger they are right now. The other correlation is how you ultimately must deal with either the rabid dog or the malignant narcissist. You don't bargain with either. You don't protect yourself by finding the 'reason' for their malignancy. You protect yourself and your loved ones first and foremost by whatever means necessary. You don't overcome them with bargains, with hope, with platitudes, with naivete. You must gain distance as quickly as possible.
We put the mad dog down because we realize there is no cure for the danger they now present to all who cross their path. While we obviously can't solve the narcissist problem that way we certainly can face facts and exile them from our lives. There is no such thing as safe contact with a rabid animal. Similarly, there is no safe level of contact with the predators hiding in human flesh.