You know i love whales, so having a whale being the one that stops the war and becomes the dark leader behind their society is cool and all.
But i don't see why that was controversial for Jack, to the point that it gave him depression, at least he was not lying saying that a big whale appeared and the war ended just like that sounds hard to believe since it doesn't actually tells you why the war would end with that, he makes it sound as if it was just the sheer sight of an animal being whale sized what made them stop.
It also doesn't tell you much about the real story, i feel like we didn't learn much from these revelations, other than the existent of a really big player behind the scenes.