Fundamentally arrogant and racist
The British establishment in those days was grossly arrogant and racist. There were remarks made - publicly - about how the bandy-legged, stunted, near-sighted Japanese could never pilot fighters and bombers successfully. Even Churchill seems to have hoped that the approach of British capital ships would cause the Japanese to flee in dread - instead of, as actually happened, licking their lips and rolling up their sleeves.
Taken all in all, war appears to be God's most successful way of teaching people that they are NOT superior to other people.
As Benjamin Franklin observed mournfully, "Experience keeps a dear school, but fools will learn in no other".