An argument can be made that the apathetic treatment of Japan after WWI in which their military support was basically forgotten after the victors promised them compensation, planted a seed for elitism in the already militaristic society of Imperial Japan. Having a powerful, elite military became the obsession of many Japanese civilians, of whom descended from/emulated samurai culture and practiced bushido. To the Japanese military, surrender was seen as the weakest, most humiliating thing a soldier could possibly do.

In the begging of the Pacific Theater, Japan had numerous victories against the United States, IE Pearl Harbor, Wake Island, and the invasion of the Philippines. Thousands of US servicemen would surrender in the Philippines alone. In the eyes of the Japanese, these men were now subhuman to them for their shameful surrender.

Basically the answer to your question is that the prospect of surrender to the Japanese was pathetic. If you surrendered you were no longer a man and shouldn't be treated as such. That relates to the incredibly high suicide rate of Japanese island defenders(35,000 alone on Okinawa), and why it took nuclear weapons to defeat Japan. In which they told their populace that they "Had not lost a war of strength, but a war of science."

They often killed Allied POWs, such as the Palawan Massacre in which 139 Americans were burned alive/machine gunned. Also the various "Death Marches" that took place in the Philippines. Japanese murder of POW's lead to barbarism of the Pacific campaigns in which the Marines adopted a no prisoner policy and often killed Japanese who surrendered. Combined that with the horrific racism on both sides and you get a stewpot for one the bloodiest conflicts in human history.