Same cognitive dissonance that prevents libs from understanding why communists either supported or were a part of every progressive movement of the last 150 years. It’s not an accident that communists were a century ahead of the left-liberals on race, gender, religion, antisemitism, and imperialism, in addition to their bread-and-butter of labor movements.

The Soviets in particular advanced the rights of women both in ideals (see the USSR constitution) and in practice (women in STEM increased significantly). The empowerment of women in the Soviet Union was so self evident that it spawned the movie trope of the headstrong, independent Russian woman who can’t be wooed by James Bond or some other “gentleman”.

It was the Bolsheviks who saw the reactionary character of antisemitism, which during the Russian Empire was especially horrible.

”It is not the Jews who are the enemies of the working people. The enemies of the workers are the capitalists of all countries. Among the Jews there are working people, and they form the majority. They are our brothers who, like us, are oppressed by capital; they are our comrades in the struggle for socialism. Among the Jews there are kulaks, exploiters and capitalists, just as there among the Russians and among people of all nations. The capitalists strive to sow and foment hatred between workers of different faiths, different nations and different races. Those who do not work are kept in power by the power and strength of capital.” — V. I. Lenin

The communists historically have been a driving force for positive social progress. Liberals co-opt these gains as products of their own enlightenment, either consciously to deny the communists a win, or unconsciously because they don’t have a theoretical basis for understanding historical development.