surely not unique to the social media age
And Americans are human: https://en.wikipedia.org/wiki/Populism_in_the_United_States
The People's Party https://en.wikipedia.org/wiki/People's_Party_(United_States) called themselves populists, and fought for: "collective bargaining, federal regulation of railroad rates, an expansionary monetary policy, and a Sub-Treasury Plan that required the establishment of federally controlled warehouses to aid farmers. Other Populist-endorsed measures included bimetallism, a graduated income tax, direct election of Senators, a shorter workweek, and the establishment of a postal savings system. These measures were collectively designed to curb the influence of monopolistic corporate and financial interests and empower small businesses, farmers and laborers."
The establishment hated this and made a full court media and institutional press to paint them as stupid rubes. Ever since everyone who the current establishment doesn't like, especially anyone who gives a shit about what voters say they want, is called a populist.
If you say so. It can also mean anti-politics.
The example you give is for left populism. There is also right populism, e.g. a large part of Trump's voter base.
> The establishment hated this and made a full court media and institutional press to paint them as stupid rubes.
Yes, when the establishment is neoliberal, they will hate anti-political movements.
Voters may not be rubes, but I find it hard to believe that everyone who was apathetic before 2016 and is now "engaged" is suddenly a scholar of government, history, and economics.
We went from political apathy to populism. This "engagement" is largely by people who don't know anything about politics and have their emotions manipulated by unscrupulous politicians and biased reporting.