That was not exactly a free democracy and those were not exactly free elections. I think it had the facade of elections, but certainly at that point there was suppression of the media, suppression of civil rights and the ability to gather and to disseminate information that ran contrary to the government's narrative.
There was obviously a significant movement, Solidarnosc, which was fighting for a democratic and free Poland. It was not entirely viewed that one participated safely in an electoral process with the knowledge that whichever way one voted would remain confidential, so an act of voting was considered an act of defiance and civil disobedience.