Bataan was just pure murder. Bushido or not....Bataan was clearly plain old fashioned murder/war crimes.
The Japanese contempt for anyone who would choose surrender over death not withstanding.
The closest film I can think of that accurately shows the Japanese mindset in the Phillipenes would be "The Great Raid" The DVD disc two features a documentary "The Ghosts of Bataan"
I dont think there is any doubt that the Japanese crossed the line from legal wartime killing to murder on a fairly regular basis. I would not go so far as to excuse them based on their "cultural" leanings of the time.
Its not hard to see how "hatred" entered the picture on a very personal level for many Marines and soldiers in the Pacific theatre of war.