Also, there is a real echo chamber that is created when you have a country that makes supporting or expressing positive DPRK sentiment illegal. Even if they are not in that country, they will still not be scouted out because it would require having a competing narrative that mines away at the myth of "savage Korea". There is also an overemphasis on testimony: the weakest form of evidence.

Edit: I refer to South Korea, which I believe makes supporting North Korea illegal.