It would be a fine question to ask, if the rest of the rethoric wasn't so biased and lacking imagination.

Haidt isn't looking into what actually happened during these periods, he's just throwing his hands in the airs preaching "I can’t see a causal path linking X with Y outside of social media".

A lot of things have been happening all around the globe that were also fundamentally different from the past, including sensitivity to corruption and awareness of global warning, which younger generation could arguably be more prone to take seriously.

A lack of clear link can't just be brushed off as a proof of irrelevance of the other probable causes.