Arguments that measure a being's worth by its thinking abilities end up ranking some disabled humans alongside animals and using them as debating props. Sentience, the capacity to suffer and feel, offers a basis for moral concern that needs no ability yardstick. Rationality as the test of personhood hurts both groups.
If ableism and human-centredness are left unchallenged, they stay on hand for any system of domination to use. Freedom for disabled people and for animals is therefore linked, and it rests on interdependence rather than independence. Each person contributes at a different speed and in a different way, depending on their abilities.
Animals are exploited on the grounds that they lack abilities humans prize, such as reason or language. This is the same prejudice that marks disabled people's lives as worth less. One judgment about capacity props up both forms of devaluing.
Industrial farm animals are bred into bodies that break down and kept in conditions that injure them. That makes the idea of a 'healthy' or 'normal' farm animal close to meaningless. Polluting farms and meatpacking plants also disable the people who work in or live near them, so they are disability issues too.
Disabled people often defend their dignity by insisting they are not like animals. This quietly accepts that animals deserve contempt. A better defense affirms human value without claiming superiority, and accepts that being an animal is part of being human.