Nature is, well, one cruel S.O.B. I'm not going to go through the litany of very cruel and violent acts many animals do to kill and eat one another. Take the Spider Wasp for example. They paralyze a spider, which is usually a Tarantula, and lay their eggs in their abdomens...usually while the spider is still alive. Once the eggs hatch, the larvae begin feeding on the spider (which is dead by now).
So for me personally, I have no issue w/ humans killing animals and eating them and I don't mind what one does with his own animals on his own land. On the other hand, I do have issues w/ those fisherman going out, catching sharks, cutting off their fins, and throwing them back into the water. Of course my Hawaiian heritage probably has something to do with me hating "shark finning."
Oh, and I have tried Foie Gras and it was not bad but not good enough for me to ever order it again...unless perhaps it was part of some bacon-centric dish!