Further, look, Progressivism does have a coherant moral structure to it. Bit HAS core moral values that if you look at and study you can make highly accurate predictions of their politics and opinions. The core moral argument they hold is that Oppression is bad, with Oppression roughly being defined as the favored culture, ideals, and economic structure of the historical majority in Western Civilization. The end goal of their ideology is exactly what they say it is: to destroy the oppressive systems and liberate people to live, basically, however they want (there is an aspect of Hedonism underlying this philosophy as well, and, well, Hedonism has been the underlying philosophical system for the Left since probably the 18th century).
I would heavily, heavily dispute this. Take for instance, the Russian Revolution. If we look at the composition of its leadership, of its actions, and its moral ethos, hedonism does not appear as a primary factor in any respect.
At the head of the Russian Revolution was of course the indomitable Vladimir Ilyich Lenin, who was infamously a "gloomy ascetic" in his own words. Lenin did not drink, he did not smoke, and it is thought that his relationship with his wife was more a of respect between fellow activists than true romantic love. With the exception of an alleged short-lived affair with Inessa Armand (one of his more trusted representatives and confidants), he appeared to be almost single mindedly focused on reading, politics, and exercise. Lenin's greatest fictional hero and possible role model was a character from the novel
What is to Be Done? Rakhmetov, a man who devoted himself to the cause with intense ardor, maintaining celibacy, scorning alcohol, sleeping in rough conditions, eating only that which is necessary to keep his body functional, and constantly exercising and reading. The book was particularly popular among the revolutionary circles of Russia, and to a degree helped shape a certain type of revolutionary. The party also contained much more chauvinist and conservative figures, like the infamous Joseph Stalin, and those as radical as Alexandra Kollontai, arguably the mother of Marxist Feminism and proponent of free love. We can thus see that Bolshevik leadership were hardly hedonistic on the whole, and it is often argued (I would say incorrectly) that the movement on the whole had a puritanical character.
Figures like Kollontai were essential in the drafting and implementation of a number of immediate reforms targeted at improving the status of women in the new society the Bolsheviks hoped to build, legalizing abortion, decriminalizing homosexuality, overhauling divorce to make it easier for both parties to file, replacing church marriages with secular marriages, and providing for the creation of state-subsidized childcare for women. In 1919, the women's department of the Communist Party's Secretariat (Zhenotdel) was founded under Kollontai and Armand, and would pursue a number of programs aimed at improving the lot of women in Communist controlled territory. Of course, what was put into place was not even close to Kollontai's full vision, seeing as it was essentially the minimum package of reforms most of the party leadership could agree on. There is no indication that most of the rest of the Central Committee were even close to as radical as Kollontai (whose radicalism in the sphere of sexual morality is sometimes overstated). Lenin would be bitterly critical of what he termed the obsession of young people with sex and sexuality instead of self-improvement and the honing of theoretical knowledge and practical organizational skills. Nevertheless, the October Revolution stirred intense moral panic amongst right-wingers in Europe and America, with titles such as
The Red War on the Family ascribing the new government a state policy of free love and even the "socialization of women". Such writers were utterly incorrect, but were joined by European leftists interested in singing the praises of Bolshevik policies, thought to liberate and demystify sex while defeating pornography and prostitution, when the reality was much less uniform, and the violence and poverty of civil war era Russia hardly lent itself to grand sexual liberation. I will forgo a description of the debates on sexuality, gender, and marriage that occurred in the 1920s for the sake of time, and because they aren't particularly relevant to my overall point.
By the 1930s Stalin and his carefully created cadre of loyalists were in total control of the Communist Party, and he had begun the Great Break in the economic sphere. During the Stalinist period, a notable rollback of previous policy in regards to women and sexuality was undertaken. In 1930, Zhenotdel was declared to be no longer needed and was abolished, homosexuality (which had never been liked among the Bolsheviks) was recriminalized in 1934, and "bourgeois deviancy" could now get citizens sent to a gulag for years of forced labor. In 1936, the Soviet regime recriminalized abortion and tightened restrictions on divorce (as well as punishments for not paying alimony), again with harsh prison sentences, declaring that it too was no longer needed in socialism (the actual concern was a drop in birthrates), and Pravda editorials and propaganda sung the praises of motherhood and the nuclear family. At the same time, dramatically heightened censorship of the arts and literature moved to impose codes of "socialist morality", suppressing discussion of topics like sex, and did away with modernism ("bourgeois formalism") and more experimental art. Thus Soviet policy continued on two tracks, one in which women were to become "full and equal citizens of their country", one in which they were to be loyal, caring mothers with lots of children, yet in both tracks neither men nor women were allowed to freely discuss matters of sexuality or of pleasure.
One can argue from this that Bolshevism was inherently puritanical, or that Stalin betrayed the cultural agenda of October, but I don't think you can make the case that Bolshevism was inherently
hedonistic. Some have attempted to contrast the "Old Left" of the Bolsheviks with the sexually libertine "New Left" emerging in the 1960s, but I think this categorization ignores the diversity in both Bolshevik and "New Left" thought regarding sexuality.
I'll cut myself off there though, I believe I am rambling a bit, and I apologize for the length of this response. I could gone on to discuss Soviet labor policy and the fight against "parasitism", or made a snippy response quoting Lenin's views on a topic, but I wanted to make a good faith attempt to reach out and explain why I think the position of "the Left" in the 20th century in regards to hedonism is a lot more diverse and contradictory than you seem to believe.