Communism has done, and continues to do, a lot of harm to the people subject to it (North Korea is above that terrible average). But how many of those people were rescued from Communism by military conflict? To help with your answer, here is a list of Communist regimes lasting more than 5 years:
- Soviet Bloc
- North Korea
- South Yemen
Perhaps you can make a case that the Soviet Bloc would have been larger if it weren't for Western European battles won by the Allies in WWII. The Korean War kept South Korea from Communism, but not North Korea.
Cambodia's first and worst Communist regime was ended by military attack and occupation by Vietnam and Laos, both of which were Communist.
But the far more typical rescues came from within -- internal government changes (essentially every other case above) and people running beyond their Communist country's borders (especially, Cuba).