He didn't write the original autobiographical story but he adapted it. The Japanese treatment of the British is indeed appalling and the British POW's are rightly outraged.
Perhaps I've just read too many books and watched too many documentaries but I couldn't help but think how they were being treated was very much in keeping with how they had treated others. The British didn't typically treat European POW's that way but certainly the non-white peoples of the colonies were treated in an often quite brutal fashion and forced to submit to the same kinds of humiliating rituals of respect and homage the British had to endure.
Did these British troops reflect on the nature of their Empire? Did they think about what they had done to others in the past? Sadly, very few ever entertain such a question, for to do so would seem treasonous and represent a betrayal of the ancestor cult that haunts every martial society.
There's more to the story and some of the themes are encouraging but feeling sorry for British Imperials or any Imperials for that matter is something that's hard to do. I feel sorry for any man who is suffering on a certain human level. I feel it much more so if he was an innocent or one misled by propaganda who was caught up in large-scale world events. But I struggle to feel a lot for people defending colonies they stole and murdered to procure.
Life is complicated and we're all placed in difficult situations. War brings out the very worst in people. I know some try to argue otherwise but morality in war is pretty scarce and almost always exhibited among those who are not doing the fighting and instead trying to help innocents. That's my opinion of course but I think one that has some theological and even historical merit. As a Christian 'The Hiding Place' is far more inspiring than something like 'Saving Private Ryan'. I admire the Ten Booms exponentially over someone like Audie Murphy.
The movie is difficult to watch but worth seeing. It's not entertainment but a movie that drives you to contemplate and consider the message being presented. I appreciate movies that are somewhat open to interpretation. It can be frustrating at times... it happens a lot in foreign movies... but as time goes on I am learning to appreciate these types of films to a greater degree.
Or, don't watch it all. There's no great loss there either but sometimes gritty black and white documentary film is like a skeleton. Watching it dramatized sometimes helps to put a little meat on the bones and flesh out a more comprehensive understanding of the context and the struggles of those involved.