From: Ontario Canada
There were reasons why these IJN ships fell to one single hit, and why other allied ones lasted after sustaining many. Damage control is one. Also, many of the IJN vessels that fell to one hit did so under strange circumstances, for example, having their decks loaded with aircraft and live bombs and torpedos.
In regards to the Kirishima, South Dakota and Washington, you have to realize the differences between these classes of vessels. The South Dakota and Washington were equipped with 9x modern 16" weapons, and had modern sloping armour (being finished months before war broke out).
The Kirishima, part of the Kongo Class, were completed, starting in 1914. They were heavily modernized, but most of this modernization took place in machenery and secondary armament, with armour virtually untouched. The Kongo also was not a battleship, but designed as a Battle Cruiser, modernized to a Fast Battleship (in reality still a Battle Cruiser, with weaker armour then any of the British Battle Cruisers). It was also armed with 8x 14" guns.
So, for the South Dakota to take a series of hits from the Kirishima and escorting cruisers (14" and 8") and surviving, while the Kirishima taking an equal number of 16" hits and sinking is not truely an amazing feat on the part of the South Dakota.
I do believe that a single IJNAF bomb hit knocked out one of the turrets of a South Dakota class, killing around 50 of the crew, and risking the survival of the ship had the magazine been hit. Imagine that one of these single critical hits takes out the ship's magazine, or aviation fuel, or some other special event.
The USS Wasp was sunk by a submarine strike, I believe either just 1 or 2 torpedos. The HMS Ark Royal was sunk by one torpedo, primarily because it was hit in the only place that one torpedo could sink the ship, anywhere else and it would hae survived (it hit the area with electiral pumps, cutting power).
Things happen, ships die after 1 hit, some take 99. Just because it didn't happen doesn't mean that it couldn't.