Here's an excellent and insightful observation from a paragraph of the essay. Speaking truth to power doesn't get much better than this:
Progressivism as played out in the last fifty years in America is the belief system of deeply unserious people. It exists to indulge a complete and utter lack of maturity and responsibility in large enough numbers that it is assured of getting its way. It celebrates vices. It must be imposed coercively. Overt fraud and deceit are admired skills. Its practitioners wallow in behaviors and beliefs that prior generations recognized as embarrassing character flaws. It is the belief system of spoiled, antisocial children and misguided enablers, rather than responsible grownups.
Rarely have I seen a working description of the Left that better comprehends and elucidates its major features.