>Why do so many people miss the point on this?

Because one party wants to return to those times with the exact same social norms. So it's a dangerous line of thinking to forget that women were walled out of many jobs, or had a huge wage gap when they were let in. As well as minorities only barely starting to really get the same opportunities after a lot of struggle.

>Like the statistics on plummeting mental health and happiness, an obesity epidemic, increases in "deaths of despair", and plateauing or decreasing life expectancy?

Yes. When it affects the majority is only when we start to pay attention.