I sometimes wonder if you really do believe this stuff, or if it's just parroting the line given by PiS.
Combined, the SLD and UD had 122 seats in a 460 seat Sejm. They couldn't cause the government to fall by themselves.
There's a very good article here that explains exactly why the Olszewski government fell. The craziest thing is that the 'list' contained the names of even cabinet members. How could the government survive if it was attacking even their own members?
nytimes.com/1992/06/05/world/parliament-ousts-poland-s-premier.html
The Government's main support comes from the right-wing Christian Nationalist party, most of whose members played peripheral roles in the struggle to end Communism in the 1980's, and were not, in general, targets of the secret police.
The most remarkable thing about this article is a comment made by President Wałęsa -
"If we allow unconfirmed information to be published, if we don't give people a chance to defend themselves, this will turn out to be the biggest victory of the security police,"
Scary to think that the same thing is coming true 24 years later, and it looks like the SB have finally won over Wałęsa.