first place. Mentally, they had to accept all was lost. At that point, once they had the power to take the emperor's life, sparing him was a moot point. I don't think this detail has any material impact.

When unconditional surrender was what America (and I believe was absolutely necessary) demanded, you have two alternatives. Accept unconditional surrender. Accept unconditional surrender following additional loss of lives. Blame Japan who, after all, did start the war. Blame Japan who did not accept surrender when it was offered.

There is a lot to consider on this issue. Atomic bombs are horrific. To excuse the Japanese at any level for their complicity in the entire conflict, including their failure to surrender on America's terms when surrender was required falls, at least in great part, on Japan's shoulders.