It is difficult to be aware of latent prejudice in our attitudes to particular groups. This is what people thought about the women's rights movement in the late 18th Century. Extending this principle is erroneous because human beings differ greatly from animals. Moral equality is consistent with different sorts of treatment and rights.
Moral equality depends on the nature of the members of the group.
Still we believe they are morally equal. Therefore such consideration should not depend on what the things in question are like or what abilities they possess, except that they have interests. Therefore racism, sexism and speciesism are morally wrong. Humans eat other species merely to please their palates. This is true because there are other more efficient means to satisfy our nutritional needs.