Why do humans care about the human rights of animals (see details)?

It is important to note that I am asking this question from a purely evolutionally point of view. I’m not asking because I don’t care about animals, but because I want to know the evolutionary advantages of caring about the human rights of animals.

I would think that any species would not hesitate to kill any other animal if it would somehow benifit the species in any way. I would think this because the other animals aren’t part of the species and therefore don’t contribute to the gene pool or to the spread of the species. This is what probably happened for most of Earth’s history, so logically it should continue today, even in humans.

But it doesn’t. I care about animals, such as animal abuse and animal testing, along with everyone I know. Why have humans evolved to care about animals? What are the advantages? Is it a gene or a meme?