Why do North Korean defectors keep changing their stories?

Why do North Korean defectors keep changing their stories? Yeonmi Park
has a history of glaring inconstancies in interviews that have left some
experts scratching their heads.
For instance, she says this about
the fate of her father: “I had to bury my my father’s body myself.” But
she’s also told reporters on another occasion that her father was
cremated. She told the Irish Times that at one point she and her sister
were forced to fend for themselves in the mountains after their parents
were imprisoned: “We had to eat and fend for ourselves, eating frogs and
dragonflies." But she gave a very different account to the BBC:
“My
sister went to live at my uncle's house and I went to live at my aunt's
house and lived there for three years.” Park’s subsequent explanation of
her varied accounts was that it was because of “a language barrier”
having only recently learned English, but such extreme differences in
narrative are clearly more than just translation errors. In the end, we
don’t know what to believe.
The same is true of other high profile
defectors. For example, former prisoner Shin Dong-Hyuk confessed parts
of his testimony that went towards writing the bestseller 'Escape from
Camp 14' were false. Similarly, former intelligence officer Kwon Hyuk
told US Congress he had witnessed human experiments. His accounts were
retold in a BBC documentary. However, South Korea’s Yonhap news agency
later revealed he had never had access to any such information. But why
is this happening? With North Korea almost completely cut off from the
world, it’s unsurprising that journalists are willing to pay a lot of
cash for “eyewitness” accounts. These days, it can be well over $500 an
hour. The juicier the details of human suffering, the bigger the bucks.
But the press then turns a blind eye when sensational claims are
disputed. Sadly, though, these lucrative falsehoods ultimately backfire,
as they enable the regime and its apologists to dismiss all claims as
lies.