One of my coworkers fled Vietnam as a 9yo because his uncle was a policeman before the war. Prior to fleeing, so much food was taken from their family farm that he was eating rats, cats, and insects to avoid starvation. The production requirements imposed on their farm left nothing for them to survive on.

I am not saying this is an inherent flaw of communism, but rather giving an example where a specific implementation was flawed to the point where someone thought they had a better chance of surviving fleeing.