The review of the new book gives no examples of any reliable evidence, so it is difficult even to assess its claims.
However, the author claims that we are ignorant in regarding North Korea as “Stalinist.” There is a difference, of course. But then to prove his point he says that there were never great purges in North Korea. The author (and reviewer) do not know the facts.
Kim Il Sung systematically eliminated all his opposition, including better-known communists. In one of his official biographies, it explains that when his forces were almost eliminated from Korea, he surprised everyone by launching a new, thorough purge. At the point when we are so weak, why does the Leader conduct a purge? people wondered. But the genius of the Leader (so his biography says) is that he realized that this was the best time to conduct a purge, to strengthen the resolve of his forces.
So there is evidence even in North Korean accounts, that purges were characteristic of the Kim regime. We have modern, first-person accounts of the prison camps in North Korea, and an interesting point is that most of them are by people who were imprisoned for rather minor reasons, or for being related to some suspected opponent. This is typical of a terror regime, and is just like Solzhenitsyn’s account in Gulag Archipelago.
My uncle was flying seaplanes at the end of WW2 and was stationed in north east Korea on the South China Sea. Planes from his group flying along the Manchurian border were fired upon by Russian planes. By then, our planes were dearmed. He mentioned this go me last week, again, saying he wanted to put the guns back in the planes and go up and get em. No luck.
Prior to the Korean war, the Stalin directed army had massacured many Japanese civilians who had settled into this area during the war between China and Japan.