People who join the military aren’t exactly known for being smart.
Or more accurately, the military wouldn’t want you if you are too smart. They want the average person that can understand basic commands without being too smart to question it.
Not surprising at all that a military person decided to do this.
Edit: On the other hand. Maybe he’s actually a genius attempting a “becoming a propaganda tool” gambit. North Korea wouldn’t lose much for treating him good, and they can make him say things on camera about how “bad” the US is. As long as North Korea deems him useful, he might actually live a decent life. But thats dependent on North Korea doesn’t just decide to get rid of him once they decide that they don’t like him anymore.