There are multiple incorrect interpretations you are picturing. I did not say every behavior that came to existence are moral. Nor is evolution itself moral. I meant that morality came to existence because of human evolution as a whole, because it allows greater growth of humans and what is greater is selected through natural selection. Well being of humans is also not well being of singular or a single family. They would often be at counter to each other. Eating and killing others is obviously detrimental to humanity even if it would have benefited a single individual.

Benefit of humanity extends indirectly to other animals. But not directly. That is, the benefit of other animal does not matter, cats and dogs included. But these animals, including farm animals, or wildlife, do bring positive value to humanity. As an hyperbolic example, if skinning cats alive somehow benefited humanity, I would consider that a moral act and our perception of that act would follow. Furthering this example, we don't consider annihilation of mosquitos (which humans actively partake in) to be immoral (just questionable consequences) because they seemingly bring no benefit to humanity.

My view on morality is not arbitrary. It is a question of what is good for humans as a whole. If yes, it is moral. If not, it is immoral.