What is the deeper meaning of Animal Farm and how does it critique the flaws of humanity?

Animal Farm is meant as a commentary on how humans act in society. Its deeper meaning is to alert ordinary people to how hard-hearted and unscrupulous leaders can take advantage of an entire population. One of the chief ways the pigs, who are in leadership, gain power over the other animals is through the misuse of language.
The pigs, for example, always have an excuse, even if a lame one, for violating the Seven Commandments. They alway pretend that what they are doing for their own pleasure, like taking all the extra apples or living in the farmhouse, is for the benefit of the other animals when, in reality, it is not. Ultimately, they reduce the Seven Commandments to one: All animals are equal, but some are more equal than others. This is a prime example of misusing language: nobody, in reality, can be "more equal" than somebody else. However, if the pigs can convince the other animals that they are "more equal," they can grab more privileges for themselves.
Orwell's underlying message is that we should push back hard against and stand up to leaders who misuse language. He is pointing out that two flaws in human nature are the desire for power over others and the tendency to want to deceive others for one's own advantage. We should be aware that almost all people have these flaws and refuse to be too trusting. If something being said over and over doesn't feel right, we should speak up. We shouldn't let more foolish people in society silence us, as the sheep silence wiser voices. Otherwise, everyone suffers.