I'd just point out that Suki Kim's book is really an ethical morass, as you can certainly make the argument that she put the people she used to work with in a terrible position.
http://www.nytimes.com/2014/11/30/world/tales-told-out-of-sc...
http://www.nytimes.com/2014/11/30/world/tales-told-out-of-sc...
A couple of thoughts just from the article:
Bad deeds do not wipe out good, nor vice versa. If Christians are helping the impoverished or teaching English because they want to convert people, that doesn't make giving a hungry person food any less of a good thing to do (this is a general example).
When she says "it's another code word for what they're doing," she doesn't go on to explain what that means. What ARE they doing? I think if she had a concrete, non-easily-objected-to explanation of the problems with what she'd observed, she'd have come out and said it. She describes their general goals, as she sees them, earlier in the article, but provides no evidence or justification for those conclusions.
In any case, assuming it is true, I don't support it necessarily - but again, it is hard for me to say "no, bad!" when they are also making a legitimate effort to help North Koreans.