The movie ignored the suffering of the local people and portrayed them as ugly and dangerous guys, while assuming the British kid deserved a nice life innately. Japanese were glorified a little in some way. The storytelling was revolving all about the kid himself, everything happens to him, around him.
I believe it's important to notice it wasn't Chinese who caused the protagonist's unfortunate experience. His family were pretty sure what they wanted, living in a colony, thus accountable for the risk of what may happen - not that they only deserve good life but not the bad one.
Ballard had the right to write about his own world that feels emotionally rich yet self-centered. But at the end of the day, it's very much his story, not history.