I would say this to people that are critical. It is very easy in hindsight to criticize a decision based on results that the decider could never have known.
He says that at the age of 14 when he was told that, he felt grateful and that the teacher was looking out for him, but in hindsight questions why a teenager should receive that information.
With barely a nod to the impending calamity, he aims not to explain what caused or was lost to the war, but to retrieve from the partial glare of hindsight the world in which it erupted.
The Fed learnt that the economy had more room to expand safely than it expected; in hindsight, it could probably have kept interest rates lower for longer.