Many people on the internet call the Palpatine family murder in Darth Plagueis to be of a cold-blooded nature when it actually wasn't. And it’s not the ultimate showcase of Palpatine’s evilness. It certainly is grizzly, but as Palpatine confesses internally while in a dilemma over Vidar Kim’s upcoming assassination, it was done out of much anger and fear. To me, it is the unmasking of evilness, revealing that it is a much more complex thing.
In the murder scene itself, it was clear that Cosigna, Palpatine’s father, was ready to take drastic measures. And, instead of dealing with it calculatedly, Palpatine’s next actions were clearly a powerful Force-sensitive’s instinctive reaction to threats. They weren’t completely conscious.
There were indicators during and after the fact that Palpatine, instead of gaining pleasure from his newfound powers and from causing suffering, was deeply disturbed by what he had done and what he could do. He went as far as to tell the rest of his family to not approach him. Although he killed them anyway sometime later, we were clued that it haunted him.
In his meeting with Plagueis afterward, he was obviously shaken by it. I personally could not detect pride in those scenes. Only confusion and terror in himself. He was expecting Plagueis to take some of that off him by showing solidarity, instead, Plagueis dumped all the guilt on him and trapped him with it. Telling him basically that he is damned, unredeemable, and that it would be a waste of time for him to try to be good.
Disclaimer: I don’t claim any expertise in either sociology or criminology. I’m as good as a layman with those. I’m just happy that finally, something may be able to effectively and efficiently explain what I feel all these times.
It is hard to pinpoint why Palpatine became the way he is. Power-hunger sure is a factor, but then it can very well be a reaction to circumstances. The thing is, we were only shown the tail end of Palpatine’s development outside of the Sith Order. We were only shown the cookies as they were just about to be taken out of the oven. But the book, through Palpatine’s own confession and others’ observation, lends us clues. And I think the theory is applicable to two of these clues.
“Precisely, you are an animal at heart.”
“King of the beast, father.”
The above is one of the most memorable snippets from the book. We all know what happens after.
The theory basically says that people might commit worse transgressions due to stigmatization (including identifying, emphasizing, and segregating) as a reaction to a previous, lesser one, or at least continue doing deviant stuff. Edwin Lemert wrote that this labelling practice alters the offender’s view of a.) the world, b.) their place in society, and c.) their sense of self, so much so that transgression becomes their central identity, a sort of reclaiming. Obviously, being deviant can be non-criminal; you just have to be something other than what society prescribes.
Looking at the quote above, I think this happened to Palpatine. The line after describes how Cosinga “knew” that Palpatine would be whatever he was when he was seventeen since long, because when he was a baby, he refused to be swaddled and fought with unusual strength. We are hinted that at home, Palpatine was marginalized, treated as an interloper by his brothers and sisters who are subservient to their father, those who “... represent all [he] can never be.” I think his circumstances fit the bill. Moreover, there is a subtextual sense of him, in the present, like a lot of people at the receiving end of labelling (even in general), embracing and yet feeling frustrated—even when you’re an arrogant antisocial rich kid who beefs with your father, it still is human nature to crave approval and membership in a community.
I think an example of labelling and internalizing also occurs when Palpatine was initiated into the Sith Order. When Plagueis said, “And of what possible use do you think a person of your nature would be to the Jedi Order? You’re heartless, ambitious, arrogant, insidious, and without shame or empathy. More, you’re a murderer.” He was actively inducing this process. Beside that, it sounds so similar to a psychological abuse tactic—it is a psychological abuse tactic—especially with Palpatine being distressed: You’re no good, you’re unreformable. You’re evil. There’s no hope for you. The best you can do is join me, depend on me. Only I and the Sith Order will accept you and make you matter.
By writing all this, I don’t mean to gauge at why or how at first Palpatine became evil (the primary cause of deviance), but how (as in the process and exacerbation) he came to that point. Nobody really knows what makes him evil. Maybe, like many of the world’s evil people, there is no one thing we can blame. I also don’t write this to somewhat exonerate Palpatine.