The article touches on poaching at Jirisan, which I looked into in the old day at Gangwon Notes.
Although I love the idea of having bears in Korea, I can’t see how it can work. Korea has a high population density and bears are famous wanderers. They will not stay inside the park borders.
Also, the reports linked to above say there are 19 bears. That sounds about right. My understanding is that one needs around fifty or more individuals before one can claim the population is sustainable in the short term, and five hundred or more to be sustainable in the long term.