The Big Picture Lesson of the 20th century was that capitalism works and socialism and communism don't. The rest of the world learned that lesson far better because they and their close neighbors suffered far more with the socialist and communist progeny of Saul Alinsky's first radical. But America should know better because it has enjoyed most the workers paradise of capitalism.
Yet those who call themselves Progressive, a polite, Americanized word for Marxist, refuse to accept that obvious conclusion. That is why our politics have become so nasty. The Progressives know they can't win a debate based on reason. So they turn to name calling, demonization, ostracism, anything to distract from and avoid a reasoned debate. Hence the widespread use of the term "dumbass" by pot smoking hippie Progressives in commenting on the reasoning of careful scholars that they disagree with, or the ubiquitous allegations that anyone who disagrees with them is lying, or bought off.
This reflects the despotic nature of the Progressive personality and philosophy. Progressives most fundamentally are certain that they are so much smarter than the rest of us, and that they are so much more moral than the rest of us. Because of that they are certain that they have the right to rule over the rest of us. It's a very anti-social attitude that the rest of us should not be expected to have to live with.
That is why they are not interested in reason. They are interested in power, for themselves, over the rest of us. In their view, they have the unquestionable right to rule, and the rest of us have the unquestionable duty to obey. The last time America was authoritatively subject to that attitude was under the reign of King George III. And, of course, you know what happened then (unless you are in public school).
That is why the Progressives are so fundamentally in rebellion against the U.S. Constitution. That governing framework was designed to preserve the rights and liberties of the people, and to restrain the powers of government and of self-appointed, supposedly benevolent despots. But if you are so sure you are so much smarter and more moral than everyone else, then the Constitution is an outdated, 18th century barrier to your imposition of your notion of the perfect society on everyone else. That is why for over 100 years now, so-called Progressivism has been an open conspiracy against the Constitution, and so at its root treason.