It’s likely true that defectors (by reason they defected) have legitimate stories to tell and they are both paid & given a platform to tell their stories by governments. Giving someone a megaphone doesn’t make their story less true does it?
When you can make a living telling stories about how awful the country you defected from is, it probably makes sense to embellish at least a few of them. It's not like anyone's going to be able to tell the awful and true ones apart from the awful and untrue ones.
I once listened to an interview with the head of the Seoul office of the U.N. Office of High Commissioner for Human Rights, and if I remember correctly she said that they had to be careful to base their work on reports from defectors because they were aware that some reports might be exaggerated or made up.
"Youtube" itself is not a source of information. It is a site where people post videos. Journalists post videos on Youtube through BBC, Economist, Washington Post, Nightline/PBS, etc...
Does their posting content on Youtube make them less credible?
Judge the originator of the content, not who hosts it.
Might as well go "Ah yes, the internet. A trusted source of information."
Probably not the current SK government. The current president is liberal side - less pro-American and more pro-peace-talk. (Conservatives would even accuse him of being pro-China, though, to be honest, that's ridiculous.)
However, SK is a free capitalist country, and NK defectors need to eat, so some of them find gainful jobs telling conservative pundits what they want to hear.
Of course there's no doubt that NK is a horrible, horrible place, but still, sometimes you have to take some of these viewpoints with a grain of salt.
I think you are kind of overlooking that the situation is a bit more complicated than just some of the defectors telling conservative pundits what they want to hear. It seems to me from a little digging that detainment of former citizens of the North by the NIS is indeed a coercive process that happens long before the defector even has opportunity to speak to the pundits. How can this be simplified so much?
https://www.theguardian.com/world/2015/oct/13/why-do-north-k...
https://www.pri.org/stories/2015-01-22/problem-north-korea-s...