smart thought. yes, definitely could be that in my opinion. Everyone wants to see people escape from North Korea, and no one wants to see innocent people get sent to a prison camp.
If that's the most likely explanation, then you're right, it's not fine journalism- it's excellent journalism. It would be crappy journalism if they decided that Occam's Razor isn't entertaining enough and they had to float a bunch of theories to get more readers. The truth is that nobody knows the answer, and that the answer may or may not be entertaining.
Well, they are examining the corpses, but that may not be conclusive: "Japanese officials are investigating the causes of death but say some of the bodies are in such a bad state of decomposition that it may be impossible to identify cause of death."