LGBT was not really talked publicly in socialist Poland, and it was never criminalised too. Typical "the state don't care what you do under your sheets" (except they did care about poplation growth and at some point there was even special "bykowe" tax for unmarried or childless males which of course hit the gays too).
Poland under socialism was about as homophobic as expected under its conditions, and thus the party was too.
This thing is either rightwing propaganda about "commies are degenerates" or part of the trend on the left of making known symbols in LGBT colours.
EDIT: the text is "ironic" anticommunism, making "fun" of supposed party propaganda, and also nothing in the text is anything about LGBT. Typical liberal take.
It would be freaking good if changed the text though.
EDIT 2, i just found an official video and decided to like it anyway, lol, they might not have the correct books but they do have the good style.