> The ships' crews were briefed on the nature of the mission and given the opportunity to stay behind if desired; none did.
Your parent post is right, the Japanese military were absolute fanatics.
Edit:
And another point. After the second atomic bombing, military officers attempted to overthrow the Japanese emperor to prevent the surrender. After the second atomic bombing. Let that sink in. If not for the heroic actions of a few Japanese men, they might have succeeded in suppressing the broadcast of the surrender: https://en.wikipedia.org/wiki/Ky%C5%ABj%C5%8D_incident
The average Japanese soldier was certainly perceived as a fanatic—due a combination of the evidence at hand at the time, deliberate Japanese policy and propaganda, and also a lot of rather nasty racial narratives—which had a lot to do with why total war was seen as unavoidable.
Another example: 21,000 Japanese soldiers on Iwo Jima, but only 216 taken as prisoners. They fought for five weeks until the bitter end. The stubborn defiance demonstrated at the Battle of Iwo Jima and Operation Ten-Go both played a role in the decision to drop atomic bombs on Japan.
There is also some evidence that Japanese Army officers created a deliberate culture of extreme violence, ordering ordinary soldiers to commit atrocities, for example, as a way of ruling out surrender as an option. The soldiers would then assume that their treatment by the other side would be identical.
I don't object to the word "fanatic" out of some semantic pedantry or because it's derogatory per se, but I think it robs us of some consideration of the individuals in question, and the various strands of policy, training, propaganda, fear, group pressure, and nostalgic death-worshipping cultural narratives to which they were subjected. The result was certainly the perception of fanaticism, which was intended to demoralize the Allies but backfired terribly, like the decision to prosecute the war itself. (And, as you point out, produced an enormous wastage of lives for no real gain.)
It’s probably foolish to say the Soviets didn’t play a part in the decisions of some of the men involved but I also strongly doubt there’s a compelling argument that it was more influential than what the Americans had just shown themselves capable of doing. The Soviets were a distant threat compared to the Americans continually bombing Japan for 3 months up to that point.
The argument goes that the Emperor's public statements were an effort to save face in front of the country. "No, it wasn't our incompetence that created defeat, they had a Super Weapon!" The Russians could have had ground troops on Japanese territory in days, compared to weeks or months for the Americans.
“They only wanted to keep the commies out” is a nicely glib line, but one that glosses over the many, many political considerations that shaped the end of the pacific war and reveals an almost total ignorance of the scholarship on the subject