I'm sorry, but how is mass imprisonment and using Machiavellian machinations of getting the population to agree with you in order to turn public opinion against the Communists not a more humane, and rather more elegant, way of putting them down instead of executing them all without a second thought?
The Far Lesser of two evils. Given the choice, I go with the 'mass imprisonment', because Communism itself is a prison for the entire population.