It is a humane principle; however, it is not humane to argue for the killing of eating animals - whom are created by the Creature, feel emotions and has a soul.
The Creator never gave us permission to take life, i.e. to termimate the life of an animal. Such words are influenced by men. Furthermore, there is proof of Torah-errors and redactions, e.g. see open lectures at Yale university [http://oyc.yale.edu/religious-studies/rlst-145].
Animals are going through a lot of pain and are treated in a way the Creator never intended and if you want to start being a part of the solution and not remain being a part of the problem, this is a great website which can help you: www.gentlebarn.org