[dragonwriter]

> Except the term "progressives" was coined by Marxists and socialists in the 1930s

Its a simple and easily verifiable historical fact that that's not when or by whom “progressive” as a political label (or even one used in the US) was coined. In 1912, former President Theodore Roosevelt—who was neither a Marxist nor any other variety of socialist—ran for President under the banner of the “Progressive Party”.

And what you suggest is also not the origin of the modern use, which was from early 1990s liberals in the Democratic Party adopting the term largely in response to decades of Republican media efforts to make “liberal” a toxic term, but also as a distinguishing marker against the rising center-right neoliberal faction of the party.