[ThrowawayR2]

Because it's been debunked over and over and over. It's just not supported by historical evidence, even by Japanese historians interviewing surviving Japanese officials. Somebody else has recommended in this thread but I will as well: "Japan's Longest Day" makes for fascinating reading.

The reality is that there was a peace faction in the Japanese government who did want to surrender but the ultranationalistic Japanese military was quite firmly in control and was very much _not_ interested in surrendering, even at the cost of millions of Japanese military and civilian casualties involved in continuing the war. (It's worth remembering that the Allied aerial firebombing campaigns had already devastated every other major city in Japan and caused far more civilian casualties than both atomic bombs did; both the Japanese and Allied militaries accepted this as part of the toll of war.) The aim (and preference of all factions) would have been a peace treaty that let Japan keep its ill-gotten gains in Asia. It took an unprecedented direct order from the Emperor to initiate the surrender, over the objections of the military. Even the high level overview provided by the Wikipedia article has excerpts like "[On August 9,] The cabinet meeting adjourned at 17:30 with no consensus. A second meeting lasting from 18:00 to 22:00 also ended with no consensus. ... The cabinet debated, but again no consensus emerged." and "As August 14 dawned, Suzuki, Kido, and the Emperor realized the day would end with either an acceptance of the American terms or a military coup." that directly contradict the idea that Japan was eager to surrender.

And beyond that, at the last minute, a coup attempt was made by fanatics willing to defy even the Emperor in an attempt to prevent the surrender proclamation from being broadcast (the Kyuujou incident).

Does any of this sound like a Japan that was eager to surrender? No, and that's why war historians generally deride this theory, quotes from Halsey, Eisenhower, etc. notwithstanding. Even just reading the Wikipedia article would make this clear: https://en.wikipedia.org/wiki/Surrender_of_Japan