You're looking for data to validate your emotions, instead of the other way around. But the memetic emotional vibes of humanity are not objective.

The link you shared appears to me to be a conclusion in search of a evidence. Unfortunately the fields of psychology/sociology are ground zero for the replication crisis.

Only 36% of study findings in psychology are even replicable, and then that number drops even more for self reported surveys: https://en.wikipedia.org/wiki/Replication_crisis

Ditto for Jonathan Haidt's entire body of work, which was based on shaky foundations.

What's more likely is you're measuring the cultural mood of the youth today influenced by current media climates (hipsterdom), instead of objective reality.

But if you genuinely think the youth of today would be happier getting firebombed during WW2, living through segregation, or working in an auto factory in the 1970s, I'd be happy to send them back there and let them see for themselves.