part of the play in it is that it's taking Communism to a crazy extreme level, where it's like "Oh your body should go to feed everyone, it's selfish to keep your limbs to yourself" but I'm not sure how successfully that comes through here honestly. You don't mention it in your comment which makes me think maybe it doesn't.

Ah, but I do:

but what if the two people in the poem were to discuss it further, if the one suggesting that they eat the arm actually convinced the other one that it was the thing to do?

You could take Communist (or a more particular ist like Leninist, Stalinist, Maoist, etc.) rhetoric and reshape it into something a silver-tongued cannibal would say, no?

Cannibalism and Communism do have this quality of self-consumption which always makes me think of Ouroboros, which is traditionally a cyclical system, but if you look at the creature itself, a snake or a dragon (drake?) it becomes clear that it can't really be cyclical, since it will eventually eat itself. Also, if it lays eggs, it will eventually do so into its own stomach.

Prions are a problem and I think that metaphorically they are present in many ideologies. For example, I lived in a Communist country for a while and it became clear shortly after moving there that very, very few people had read The Communist Manifesto. Instead, they were told things about Marx and his work by people who were also told about the work, but had never read it and that this had been repeated several times. Thus, their beliefs and ideas about what Communism should be in theory and in practice were formed by an (most likely intentionally) imperfect transmission of the the original ideas.