I'm more worried about the lower tail end of the bell curve that doesn't get the memo, and they become increasingly deranged. When 1/4 of the public is essentially brainwashed, your society is in deep trouble.
On a more serious note haven't societies long been based upon common brainwashing? The Bronze Age and before are fuzzier on the details but propaganda certainly existed then as well at a smaller scale.
Technology advancements raise the danger potential almost exponentially when compared to late history, or even recent history.
It doesn't take much to tip the course of history. The bronze age didn't require the same type of risk assessment that we have the burden of managing.