> Their anonymous responses were transcribed and sent back to me
This doesn't pass the smell test for me, this journalist never directly met or claims to have verified the identity of anyone that they are speaking to, the contacts were provided to them through unspecified "South Korean contacts" (are these contacts independent? not affiliated with SK state sponsored anti-NK propaganda initiatives?).
Of course they shouldn't be explaining who exactly is giving them these testimonies but it makes it very convenient to say 'I got this information from super secret sources, you'll just have to trust me that they are unbiased, forget the fact I am working for a USA based publication'
The single video that is actually shown simply shows the sort of seafood processing factories you see all over the world, nothing that proves anything specific about the accusations. Furthermore, this hasn't been accompanied by any release of the supposed documented evidence (with suitable redactions). I also love the use of handwritten testimonies to visually make the article look like it's backed by evidence, when this is the very evidence which has no established veracity.
I've seen how the USA media love insinuiating things through 'anonymous sources' about Iraq and countless other 'unfriendly' countries to justify devestating military invasions or economic sanctions on foreign countries. All to simply to enrich their own bottom line, keep the US Dollar flowing and keep their stronghold on resource extraction from poorer countries.
For a counter-factual, see this video with interviews with actual NK people living in SK on how NK defectors are treated by SK government, including testimony from a lawyer who has publically worked on defending them: https://www.youtube.com/watch?v=3V4Hnl7J9H4&list=LL&index=2