Yeah that's not evidence. Yeonmi Park could write a library full of books of her fantastical fairy tales and it still wouldn't constitute evidence. What makes these authors any more trustworthy? Has any part of their story been verified by independent sources? Do they cite any verifiable evidence for these claims in their books and articles or just more of the same alleged hearsay and anecdotes?

The US and its puppet regime in occupied Korea have a documented history of coercing and bribing defectors into telling stories which many of these people later themselves admit were total fabrications.

When reading books written in the imperial core, about the enemies/targets of imperialist nations, I would keep this in mind:

Former CIA case officer John Stockwell: Well for example, in my war, the Angola war, that I helped to manage, one third of my staff was propaganda. [...] We would take stories which we would write and put them in the Zambia Times, and then pulled them out and sent them to a journalist on our payroll in Europe. But his cover story, you see, would be what he had gotten from his stringer in Lusaka, who had gotten them from the Zambia Times. We had the complicity of the government of Zambia, Kenneth Kaunda if you will, to put these false stories into his newspapers. But after that point, the journalists, Reuters and AFP, the management was not witting of it. Now, our contact man in Europe was. And we pumped just dozens of stories about Cuban atrocities, Cuban rapists--in one case we had the Cuban rapists caught and tried by the Ovimbundu maidens who had been their victims, and then we ran photographs that made almost every newspaper in the country of the Cubans being executed by the Ovimbundu women who supposedly had been their victims.

Interviewer: These were fake photos?

Stockwell: Oh, absolutely. We didn't know of one single atrocity committed by the Cubans. It was pure, raw, false propaganda to create an illusion of communists, you know eating babies for breakfast and the sort. Totally false propaganda.

Interviewer: John, was this sort of thing practiced in Vietnam?

Stockwell: Oh, endlessly. A massive propaganda effort in Vietnam in the '50s and in the '60s, including the thousand books that were published--several hundred in English--that were also propaganda books sponsored by the CIA. Give some money to a writer, "Write this book for us, write anything you want, but on these matters, make sure, you know, you have this line."

Interviewer: Writers in this country? Books sold and distributed in this culture?

Stockwell: Sure. Yeah. English language books, meaning an American audience as a target, on the subject of Vietnam and the history of Vietnam, and the history of Marxism, and supporting the domino theory, et cetera.

Interviewer: Without opening us up to a lawsuit, could you name one of them?

Stockwell: No, I could not. The Church Committee, when they found this out, demanded that they be given the titles so that the university libraries could at least go and stamp inside "Central Intelligence Agency's version of history," and the CIA refused because it's been commissioned to protect its sources and methods, and the sources would be the authors who wrote these false propaganda books, some of whom are now distinguished scholars and journalists.

Source (video interview)

Also note:

• It's a recognized problem in south Korea that "time and time again, conservative outlets and foreign media circulate and reproduce rumors [about DPRK] based on questionable sources ... retractions and apologies are rarely ever provided when the reports are shown to be false" and "Sometimes, the South Korean government itself has been the epicenter of false reports ... The situation has been made worse by defector groups aggressively proliferating claims from unverified 'North Korean sources,' as if attempting to draw attention to themselves."

• South Korea's national intelligence service (NIS) forges documents to frame people and tortures them into false confessions as well as pays defectors for sensational stories and harasses and silences people who say positive things about DPRK (and takes away their passports so they can't go back, even when they came to south Korea against their will)

• UN human rights researchers who have worked directly with defectors from DPRK have written about how testimonies are made unreliable by cash incentives paid by the NIS and other organizations: "North Korean refugees are well aware of what the interviewer wants to hear. ... The more terrible their stories are, the more attention they receive. The more international invitations they receive, the more cash comes in. It is how the capitalist system works: competition for more tragic and shocking stories. ... In my 16 years of studying North Korean refugees, I have experienced numerous inconsistent stories, intentional omission and lies. I have also witnessed some involved in fraud and other illicit activities. In one case the breach of trust was so significant that I could not continue research."

Edit: So, to summarize -- Former CIA case officers have discussed how they pay academics and journalists to write thousands of books about foreign communist enemies that contain whatever content the author wants as long as it pushes certain specific lines; the CIA regularly plants false stories into foreign newspapers and gets them circulated around; the NIS (formerly the "KCIA", formed on the US-backed side during the Korean War to combat communists) is known to forge documents, extract false confessions, pay people to lie or embellish to the point that mainstream south Korean liberal media and UN researchers say it's making it too hard to tell what's true; defectors with sensational stories receive payments and get book deals and international speaking tours while people with positive things to say get arrested and surveilled by intelligence agencies...So, keep that info in mind as you consider what's going on with these books.

"Whatever is written in a book is right — such is still the mentality of culturally backward Chinese peasants. Strangely enough, within the Communist Party there are also people who always say in a discussion, "Show me where it's written in the book." When we say that a directive of a higher organ of leadership is correct, that is not just because it comes from "a higher organ of leadership" but because its contents conform with both the objective and subjective circumstances of the struggle and meet its requirements. It is quite wrong to take a formalistic attitude and blindly carry out directives without discussing and examining them in the light of actual conditions simply because they come from a higher organ. It is the mischief done by this formalism which explains why the line and tactics of the Party do not take deeper root among the masses. To carry out a directive of a higher organ blindly, and seemingly without any disagreement, is not really to carry it out but is the most artful way of opposing or sabotaging it.

The method of studying the social sciences exclusively from the book is likewise extremely dangerous and may even lead one onto the road of counter-revolution. Clear proof of this is provided by the fact that whole batches of Chinese Communists who confined themselves to books in their study of the social sciences have turned into counter-revolutionaries. When we say Marxism is correct, it is certainly not because Marx was a "prophet" but because his theory has been proved correct in our practice and in our struggle. We need Marxism in our struggle. In our acceptance of his theory no such formalisation of mystical notion as that of "prophecy" ever enters our minds. Many who have read Marxist books have become renegades from the revolution, whereas illiterate workers often grasp Marxism very well. Of course we should study Marxist books, but this study must be integrated with our country's actual conditions. We need books, but we must overcome book worship, which is divorced from the actual situation.

How can we overcome book worship? The only way is to investigate the actual situation."