A writer asserts his point of view in all kinds of ways, and one of them is characterization. In general terms, the most negative aspects of Communism are depicted by the animal with the most negative connotation--a pig. We use the term pejoratively to describe people who are selfish or greedy or dirty or smelly. All negatives. It's no coincidence, then, that Orwell chooses pigs to represent the worst of what Communistic leadership is. It's not just the leaders who are to blame for the negative aspects of Communism; those who don't educate themselves or keep a watchful eye on the government are willing participants because they're too uninterested or unaware or uneducated to be a factor for change. Guess who these people are in Animal Farm--the smelly, dumb, easily moldable sheep. Conversely, the hardworking people are represented by the loyal and hardworking Boxer, a horse. This, too, is evidence of Orwell's belief that the working man is exploited and oppressed by a selfish and cruel Communist leadership.
In my opinion, Orwell thinks that communism is a fine idea in theory but that it gets to be corrupted by the people who take power. I think that we can see this in the following ways:
- Old Major's speech makes a lot of sense. He is right that the people oppress the animals. It seems plausible that the animals should be able to govern themselves more humanely. This tells me that Orwell agrees with Old Major -- he makes his ideas sound good.
- Boxer is perhaps the most admirable character. If everyone worked like he does, the farm would be a success. This shows that Orwell has sympathy for hard-working laborers.
- The pigs are greedy and oppressive. This shows us that Orwell believes that the leaders of communist countries have (and always will?) forget their ideals and instead take power and wealth for themselves.