Moral Hierarchy is a compelling idea because it gives human moral priority while granting non-human beings moral values. Still, this concept has some flaws that resulted real-life problems and animal suffering such as animals in zoo captivity committing suicide.
These issues happen because the guidelines of how human as moral higher beings should treat animals are vague. Sterba’s idea of the 4 principles lack specification that created loopholes for people with personal desires to misuse the term basic needs (which is the base of the four principles) As a result, unjust treatment of animals are disguised under the excuse for basic needs.
It is possible to define the term basic needs with Maslow’s hierarchy of needs. Once the term is clarified, some loopholes will be closed. It is also important that there is a common understanding of basic needs. The power of majority is strong and can push for actual changes of the flawed system causing animal sufferings.