The collection of Hoover Institution Archive
Polish independent publications collection, 1976-1990
is likely to consist mostly of documents manufactured under the guidance of the Polish communist dictatorship. The reality in Poland of that period was such that no independent activity was possible. You did not have to do any "underground" activity in order to be thoroughly controlled by the communist secret services. If you were classified as a communist enemy, your life was quietly surveilled and often sabotaged, much like the Die Zersetzung program of the East German Stasi. This was common practice in the communist countries of Eastern Europe.
It is absurd to claim that there were groups of people doing extensive "underground" activity. Well, they did it on orders of the communist authorities, who organized fake opposition to themselves in order to fully control the situation.
If anything, the collection in the Hoover Institution Archive is an excellent example of a communist provocation/simulation.