When discussing "Animal Farm", the book is usually labeled as an allegory to the formation and eventual corruption of the Soviet Union under the rule of Joseph Stalin, but are there any other political historical people or events that readers might find similar to those in the book? These historical parallels can take place after the book's publication.
Example: The construction of the windmill is similar to The Great Leap Forward under the rule of Chairman Mao Xedong of China, as both were ambitious projects which required the hard work of almost every citizen, with the promise of a more relaxing future to result from these projects, and both projects had greatly negative impacts on the people (mainly starvation).
I would argue that the book is an allegory for the revolutionary process in general. Any kind of revolution follows this basic format. There is a well-respected visionary whose ideas are taken, and eventually corrupted. There are a few true believers, some who go along for the ride, and some who are ambivalent. Things start out rosy while everyone is patting themselves on the back, then problems develop. Eventually, things get so bad that the new status quo is just as bad or worse. Eventually, the novelty fades.
Any time you have hypocritical actions by a government, they can fit into the allegory presented by Animal Farm. You could look at the fact that we claim to have an interest in reforming and rehabilitating prisoners in our prison system (and since we imprison more people per capita than any other nation, that would be a good thing...)
Yet we imprison people in incredibly barbaric places without access to real opportunity to improve their situations, etc. We put them in systems that encourage more violence, more scheming, and more crime in order to survive, and then make it really difficult for them to get jobs when they get out of prison.
Surely this is a system designed to help our society grow, etc.
Of course, labelling anything in this way is politically sensitive because the people we compare to those in Animal Farm would probably not agree...
As far as the idea of rebelling and then acting no different from the people you overthrew, I would point to perhaps the Iranian Revolution. It overthrew the Shah and then acted just as repressively as he had. Or perhaps you can look at the Mexican Revolution of the 1910s that was supposed to bring more power to the people but really ended up keeping it firmly in the hands of elites.