I’m saying that defectors may leave not because they believe the system itself is bad, but because of certain economic crisis inflicted from the outside. Further, some defectors leave for the ROK and find life worse than they expected, or are in some cases are kidnapped by the ROK after being lured into overseas programs. There are well-documented cases of this, which is why my comment has lots of sources, so if you want more then please see it.

Nodutdol, an anti-imperialist group of Korean expats, released a toolkit on better understanding the situation in Korea. This is more like homework, though.