Justin E.H. Smith:

I am growing increasingly convinced that people who believe we have an absolute moral duty to see to the well-being of all other human beings, to install water-purifying equipment in villages on the other side of the world, etc., and who, at the same time, happily contribute to the ongoing mass slaughter of animals, are really just picking and choosing their causes. There simply is no compelling reason why I, or anyone, should suppose that all and only human beings are the worthy targets of moral concern. This is not to say that you should care about animals. It is only to say that there is nothing natural or obvious or conclusive about your belief that you should care about all and only human beings. Your belief is a prejudice, characteristic of a time and place, and not the final say about where the reach of moral community ends.

I completely agree, and this is why I would never identify as a humanist.