Thatcher met with Gorbachev and personally begged him to do whatever he could to prevent East Germany from merging with West Germany, guaranteed protection for Communist rule in Soviet-bloc nations, and offered a unilateral non-aggression pledge to the Soviet Union itself. George Bush and Francois Mitterand, right-wingers who also presided over noisy anti-communist parties in their countries, backed her assurances to the Communist leader and pledged themselves to prevent German re-unification in any way they could, including with military alliances with the USSR against their official ally West Germany.
What should be a source of disgust, and even outrage, is the very public discovery of what many of us believed all along - that the entire Cold War was bullshit from start to finish. Far too many human beings, whole countries in fact, were decimated by leaders who pledged adherence to a political ideology and practical policies they not only didn't believe in, but sought to undermine just as the goal of those policies was about to bear fruit.
One note: Mitterand was a socialist, not a right-winger.