I think the Koreans in the north are much less brainwashed then they are portrayed. They all live in fear and under a very real and immediate threat of being picked up for inquiry and sent away to a camp. They are also dirt poor and many suffer food shortages to the point of hunger. So people aren't that stupid to live in such conditions and still believe they live in an utopic socialist paradise. And surely they have heard about living conditions of their neighbors in China and down south, where many of them have relatives.