It's a symbolic protest against the new lustration law. Geremek supported the lustration of both elected officials and the most senior government ones - i.e. including himself and has previously submitted the required declaration. What he's objecting to is the mass lustration - rather than a few thousand people, many hundreds of thousands, and serious due process problems with the verification process. Also, this isn't about 'have you ever been a communist' it's 'have you ever worked for the secret police'.

Under McCarthyism it was any association with the CPUSA - admittedly a pretty ugly party, but it was both insignificant and went beyond actual membership to even the most tenuous levels of cooperation. As the CPUSA sought to infiltrate and control a whole host of organizations devoted to progressive aims, e.g. anti-fascism and civil rights, it had the intended de facto effect of blacklisting most people active in progressive causes during the thirties and early forties. Here we're talking about working for the secret police under a dictatorship. For elected officials if you did and admit it you're not subject to any sanctions. The new law, however, is a bit vague on what's to happen to, say, civil servants or journalists, or academics who admit to working for the SB.