In Animal Rights/Human Rights: Entanglements of Oppression and Liberation, David Alan Nibert discusses the theory of oppression. While the book does a good job discussing the theory of oppression (illustrated above) as it is applied by other animals, it lacks an equivalent discussion of a theory of anti-oppression.
According to Nibert there are three basic factors of oppression: 1) economic exploitation/competition; 2) unequal power, largely vested in the state; and 3) ideological control. In terms of the oppression of other animals these three factors are: 1) the exploitation of other animals; 2) human supremacy; and 3) speciesism. Given these factors, veganism offers the basis for a theory of anti-oppression.
First, veganism is fundamentally about addressing the primary factor of oppression. That is, veganism is a theory and practice that rejects the exploitation of other animals by humans. Addressing exploitation as the root of nonhuman animal oppression is essential.
Human supremacy, the second factor of nonhuman animal oppression, is based on exploitation as the primary factor. This is because the primary force that keeps the structure of human supremacy in place is the material and psychological gains that come to human animals.
Speciesism, the third factor of nonhuman animal oppression, exists to perpetuate the system of human supremacy. Which, as already noted, is based on the exploitation of other animals.
Succinctly linking all three of these factors in a speech on veganism in 1947, vegan movement co-founder Donald Watson noted that vegans believe that if we are to be true emancipators of other animals we must renounce absolutely our traditional and conceited attitude [speciesism] that we have the right [human supremacy] to use other animals to serve our needs [exploitation].