At the highest level the goal is to foster development of moral values and ethical decision making ability. Moral values are a person's sense of right and wrong. Not every possible choice or event in life is necessarily defined in one's list of moral rights and wrongs. And, some choices and behaviors and their implications are not clearly right or wrong, if the subject has never been considered, or if the result of the behavior is not known. Many people have acquired morals, and follow their own moral values, but they may also be ignorant of the result of some of these values. For example, we might enjoy watching animal entertainers and "love" and feel empathy for the animal character, and for similar animals. But, if we know that that animal entertainer suffered and was mistreated in order for the performance to be accomplished, we might no longer believe that enjoying that entertainment was something we could be morally comfortable with.
Ethical judgment is not quite as simple as "moral" judgment. Ethical judgment implies the weighing of competing values or competing right (or wrong) choices, and involves multiple (competing) stakeholders. One of the competing stakeholders might be our own "moral" beliefs and values. Another stakeholder might be society, if our personal moral belief conflicts with the good of a larger group, or even 1 other individual. An ethical choice or decision will be more than just what I believe is right or best; it will also weigh what is best for some other person(s) or stakeholder(s).
There are many reasons why attitudes (beliefs, values, ethical choices) toward animals impact our society, the world, and individuals. One person's neglect becomes the community's problem. One animal's freedom to roam, and/or lack of neutering produces unwanted strays (who will suffer and cost the rest of the community), and destruction of bird and small animal populations, and places the animal at risk of cars and predators. Beyond such practical reasons to learn about responsible "pet" or animal "ownership", attitudes toward weaker and perceived "inferior" species or groups of humans follow the same logic that is used to justify destruction of other peoples, and even the environment. That is a hierarchical view in which supposed superiority, and superior strength has been used to justify war, genocide and even slavery.