Yes indeed: these campaigns of hatred &c developed especially in the past 10 years, as a way of distracting people from the rise in income inequality that started with the Reagan Admin. The article partially addresses this, but not appropriately:

Spoiled elites—highly unappreciative of the New Deal’s populist approach and the decades of labor battles that created the pressure for change—turned a blind eye while corporate America worked diligently to return the American economy to Gilded Age levels of inequality and worker disdain.

and

[Michael Lind] “We become Peron’s Argentina,” he answered, without missing a beat. “It’s where I think we’re going to end up anyway. We’re showing signs of it ... your capitalists are mostly a rentier class, living off unearned income from banking, agriculture, finance, or stock sales … elites tied to the military and a nationalist coalition of interests. The working class is immobile. It cannot move at all.”

It's well-known that the "happiest" countries are known for a greater percentage of wealth parity, the middle class, social programs, healthcare &c, such as: Finland, Denmark, Switzerland, Iceland, Netherlands, Norway, Sweden, Luxembourg &c.

I don't think most Americans hate one another, and the statistics do not show this. I do appreciate the approaches in the article, which cover interesting points. The news media and social media post many times on a daily basis videos of the craziest Americans, which makes these media complicit in reinforcing the idea that Americans hate one another. The vast majority of Americans are still known worldwide for being among the nicest, warmest, most generous people in the world. They're also known for their gullibility, relatively high poverty statistics for a "first world" country, and racists. What the article could address more specifically is that political corruption is eating away at the American Dream, which will be unattainable for most young people. The solution - in my view - is to vote out of office all of the old politicians, and replace them with people who have a record of supporting the 99%, at the expense of the 1%.