There are complexities, but every issue can be simplified. I think economic inequality can be boiled down to a few key issues:
1. The Imperial War Machine: Iraq/Iraq II/Libya/et al -- very expensive, no economic return for anyone but the military-industrial complex [0]
2. Economic warfare on Mexico/et al [1] in the 1980's -> Economic Refugees
3. Free Trade -> more economic refugees (NAFTA put Mexican subsistence farmers [2] in direct competition with mechanized agriculture)
4. Cost-disease: medical-industrial complex edition
5. Concentration of wealth -> investors seeking returns for their investments.
[0] https://www.cnbc.com/2017/01/18/chinese-billionaire-jack-ma-... [1] https://en.wikipedia.org/wiki/Confessions_of_an_Economic_Hit... [2] https://en.wikipedia.org/wiki/Subsistence_agriculture
Beyond that, annoyance at entrenched, unworthy incumbents is something that people from many political backgrounds could agree on. I expect many left and right leaning folks could find common ground in wanting solutions to the nasty economic traps that made middle America so discontent in 2016.
For me, the Trump administration and current GOP has been a good example of this. I am the last person you'd identify as a Trump supporter, but there are policies (e.g., FDA deregulation, maybe some school deregulation) that I think would be healthy. But overall, the policies being pushed by his administration and the party pick and choose things so that the libertarian approach gets grossly distorted. In general, I am libertarian, but I don't trust the GOP to implement it, because often what you end up with is some Frankenstein monster of policy that is more fascist than libertarian.
Too often, good policy theory--whether more libertarian or socialist--get distorted by the time they get to actual politicians. "Capitalized profit, socialized risk" is what you get as a result.
On another note, I don't see this as a series of angry platitudes--many of the points they're making have been made elsewhere in more rigorous outlets. This is a piece that's trying to explain the principles to others.
And I worry that what we often need as a society as dismissed as "angry classism" when it's just really anger, because people are suffering.
I work in health care and I am acutely aware of the problems with licensure and regulation. There are reams of unnecessary regulations that increase costs, and there is a strong regulatory capture regime in the form of regulations that put physicians at a top of a hierarchy, that result in huge cost increases due to lack of competition. There have been volumes of studies showing, for example, that this hierarchical decision-making system is actually less safe, and that many roles currently legislated to physicians or other providers could be done by still other providers, such as optometrists, pharmacists, psychologists, and other providers.
What I see, though, is whenever someone suggests deregulating health care, there are cries of "you're trying to decrease safety for economic benefit." It's absurd to me because the current regulations are often not based on any scientific studies, and when there are studies, they often suggest the regulations are unnecessary, or decrease safety. But at the same time, I understand these source of these concerns, because when deregulation happens, it often happens selectively, in such a way to benefit a small few at the expense of many.
I'm very depressed by health care debates in the US, because they often are reduced to discussions about socialized versus capitalized payment systems, with little to no discussion of alternative regulatory systems, or transparency. To me, working in the field, the question of who pays huge costs is a symptom, not a cause, of problems in the system. I was very supportive of Obamacare, not because I saw it as the best solution, but because I hoped it would force politicians to start addressing sources of cost, especially the GOP who should be all about deregulation. Instead, they failed their opportunity, and turned it back to useless discussions about who should pay.
My least favorite thing about politics, the national conversation, and resultantly the media is weak platitude based arguments that willfully ignore the complexities surrounding virtually every issue we face today.