You people seem to hugely underestimate the near idiotic sense of duty the Japanese had. When you had an order, you stuck to it. Retreating or surrendering was unacceptable, which led to serious problems when Japanese commanders tried to pull back units out of dangerous positions. They'd refuse to go and got killed for no reason.
It's also why Japanese treated prisoners of wars with little respect - They had done the most shaming thing possible, in their eyes. Western civilians were seen as the source of all evil in Asia, and Chinese as lesser beings. The Japanese did some pretty odd stuff which we, with our western brains, can't grasp. What we see as almost a medical condition, can be seen by the Japanese as just a good sense of duty/honour.
This man is not the only one. There were, as said in the article, hundreds. In China and Korea, even Borneo I believe. They'd just continue being soldiers, not even because they had been ordered to hold a position but simply because retreating or surrendering was unthinkable. Try finding a single western soldier from World war 2 that retreated into some big forest and refused to surrender.
The way the Japanese look to World war 2 and the actions they committed in it, is what remains of this 'sense of duty'. The feeling of 'Wrong? How do you mean, wrong? They just did their duty". That's even what they apparently get taught in school. Despicable in our eyes, but not in theirs.