Animal Farm is not an anti-communist book. The first half captures communism working perfectly well under the rule of the Lenin-Trotsky analogue - the animals work hard, are well-fed, and organise themselves to create new industry - the windmill - with the goal of eventually eliminating the need for labour.

Everything goes to pot when the Stalin-analogue takes over, because the book is a reflection of Orwell's opinions of the Soviet Union and his experience fighting with the communes in Spain and the subsequent purges committed Stalinist factions against the Trotskyists. If you read the Ukranian prologue, which is included with most modern published editions, Orwell even outlines that Animal Farm is an attack on Stalinism, and he firmly believes in socialism.