Lefties have no more right to call themselves progressive. The progressive movement that exploded at the beginning of the 20th century was a direct descendent of the People's Party in the late 1880s and 1890s.
Lefties do not hold any of the values of the progressive movement. I am a progressive, especially as a Californian who lived in the Progressive era and worked in the Legislature at the end of it.
In the 1950s California was the leading state in education, freeways and honest government as well as supporting a rapidly growing economy attracting new business and new technology.
The core ideas embedded in the California government by the Progressives were government employees selected and promoted by civil service exams, elected political offices without any party affiliation, open primaries, open public documents and policy available to the public in the form of initiatives and referendums.
Every single bit of the Progressive agenda was completely destroyed by the Democratic party in 1960. By 1962 the Democratic Party had wiped out nonpartisan elections and built a giant union based money machine for electing only Democrats at state and local levels. Transparency was eliminated.
Decent people no longer ran for office. California became the cesspool of education, union corruption in government and incompetence at every level of government. Non-progressive Democrats destroyed California.
For the modern Democrats to call themselves progressives is simultaneously a farce and an insult to the history of the real Progressives.