Also, this scene marks the total degradation of the original values the animals had when they first started the revolution. They did not start a new society after all. Instead, the pigs became just as power hungry as the men they set out to replace. Instead of living in equality, the pigs simply replicated the imbalance of power that they were outraged by earlier in the novel. The power in this scene is in the parity the pigs have achieved with the humans. They are corrupt, and everything the animals worked for has been lost.
Orwell was making a comparison of the uneasy alliance between the soviets and the allies. The humans and the pigs compare the problems of keeping the lower social classes in line, that it takes vigilance to keep them in their place. Just as with that situation, there is no real trust between the humans and the pigs, and for the regular farm animals they lose all hope.