The chief point of Animal Farm is that workers are stupid, helpless, and doomed to follow whatever the intelligent people of society say, and that these intelligent people will only ever work in their self-interest. Orwell had to grapple with his own opposition to the USSR and Stalin, as well as the popular support both enjoyed internally. So, he did what he did best, take an aristocratic viewpoint and force it through allegory rather than center the working class as the maker of history.