All you should need to say is there were famines every couple of years before the communists came to power. After they came to power there was a single famine. There were no more famines after that. If communists really wanted to cause famines wouldn’t they have allowed/forced even more afterwards? They didn’t, and the lack of famines also showed that socialism eliminated famines. And now they’ve eliminated poverty striking a strong blow to general food insecurity too.