Firstly I am not an expert but allow me to give a little limited input.

Propaganda spread by the CIA/US, a reactionary national character and some shortcomings of the system.

Obviously the US had Radio Free Europe which sent propaganda into many countries but this was not the only mechanism. The Soviets did not practice total information control nor prevent people from leaving to go on vacations so you have propaganda as well as glowing stories of what the west looks like (two cars for every family, two chickens in every pot, etc) that they were never going to achieve because the imperialist capitalist core desires to subjugate and exploit them, not give them a US quality of living. But they believed this, they believed in the Potemkin village of West Germany.

Poland honestly has always been in the last 100 years pretty reactionary and really even before that. For hundreds of years you had pogroms against Jews in Poland. Poles happily abetted the Nazis in exterminating Jews and others in the holocaust, there is a reason a number of death camps were in Poland. They now deny this active collaboration and you can see that Poland is a reactionary hell-hole these days and getting worse. Some of this is down to the religion, large amounts of the populace are Catholic. Not your ever so rare liberation theology extremists, nor your Church 5 times a year casual Catholics, but backwards, bigoted, hateful, weird, traditionalist diehard Catholics. The kind who hate gays, hate people different from them, are very judgemental and so on.

The Soviet Union by the 80s had problems. There were revisionists, there was corruption, there were many problems and the whole thing was beginning to look rusted and tired because of these. This is deserving of an entire post or several so I won't go into the details. Let's just say the golden period had passed and more people were growing pessimistic and cynical about the whole thing.

The first part is most important, they were convinced by the propaganda, by the standard of living in the west (that they were never going to have and still don't), and by leaders helped directly by the CIA, US State Dept, and so on that they could have their cake and eat it too. That they could overthrow this imagined brutal soviet communist rule and install some sort of friendly rule through the people directly via local unions and thus have the western standard of living and opulence as well as independence while retaining workers rights and power. This of course was a lie.

This article both shits on Jacobin (their foreign policy takes) and gives some background on Poland and how Reagan and the Pope teamed up to fuck everything for everyone in there.

A similar thing happened in Czechia. City dwellers were upset at working hours and lack of improvement vs western cities, whereas the rural areas were heavy supporters of the Communist government because they built a ton of stuff in rural areas.

Just found this which is interesting https://culture.pl/en/article/the-solidarity-movement-anti-communist-or-most-communist-thing-ever

Because the government started implementing austerity measures, and people were self organizing strikes after initial requests to end austerity got people fired from their jobs. The CIA funneled money to the more moderate parts of the Solidarity movement, but there were hundreds of thousands of members wanting more radical action to self organize their production, so much so that frankly the CIA tried to use their moderate members to reign in the radicals as they were doing too much.

The movement already had hundreds of thousands of people in it before there was any money sent to it. After money started, the CIA gave 2 million a year for 5 years. The money was channeled through third parties. The NED funded organizations that promoted Solidarity abroad but had no money links to the organization itself. The AFL was much more direct, and solicited hundreds of thousands from individual union members to send to Solidarity. What was this money spent on? Most of it was spent on paying workers in Poland who got fired for political organizing. The CIA was so paranoid about being found out that they had virtually no contact with solidarity, and quite literally none with the dissidents in the underground, so much so that CIA reports complain about radicals using their money for stuff they didn't want them to. For example, they repeatedly complained internally that there efforts to quell the revolutionary tensions failed, and they were being exacerbated. The money allowed a set of professional organizers to do underground publishing and activism full time, however they acted independently on what to do with that money. Why did they succeed? Because the polish people were so pissed at the government that they went on strike. Now there was a marked difference in the two phases of the union, with the latter being more moderate (due to the funding), compared to the first phase pre martial and shortly after the martial law declarations.

Lol at the Ben Norton article in here, just totally ignores the majority of the movement and the reason it existed.

The CIA