I always found it an interesting theory, but one with it's own major flaws. To go in order of the article...
1) Timing. The article glazed over this... but the surrender vote was in fact. Deadlocked. Members of the Japanese peace faction directly credited the Nuclear Bomb as what allowed the emperor to push the peace option.
They called the nuclear bombings a "Gift from Heaven" which... even under American occupation would be a ridiculous thing to claim otherwise.
Fear of Russian invasion making their defense plan useless may have been what caused the surrender vote to come about.... but it wasn't what pushed through the final surrender.
Also, i'll note the article makes the awkward arguement that both the Japanese knew too much early, and too little late. (Though doesn't consider for example, some people knowing a lot early, and others having to be read in on what a nucler bomb was from those who already knew.)
2) Scale, ignores the main fear of nuclear weapons, even before they got big. Which is that it literally only takes one bomb. There is no real defense or chance of inflicting casualties.
Sure the Nuclear bombs weren't near the worst bombings to occur in the war, they however were the most "unfair."
At this point instead of trying to cause deaths here and there and negotiate for a better peace it just becomes something a lot more hopeless... even in the terms of just trying to lose but eek out something of value.
Russia was no doubt a major fear and played a big part in it... but Nuclear weapons in the end seems like what forced their hand.
