As humans, we do get to choose what we eat, and when we choose to eat a plant, we are eating (i.e., harming) just that plant, plus indirectly whatever nutrients that plant consumed over its lifetime (and we are also harming whatever beings may have been living on that plant or who were injured or killed in the harvesting process). But when we eat an animal, we are eating not just that animal, but also indirectly all of the plants and other beings that that animal ate over its lifetime - those plants became the flesh that we eat.
Sharon GannonHave you seen how fish are able to swim in a school so precisely relating to their fish-fellows and never clumsily bump into one another? That's because they have a highly developed sense of feeling in their bodies, which enables them to feel not only the movement of the water against their skin but the presence of other beings who are close. They certainly are not cold-blooded in the sense that they are dull, insensitive, and have no feelings.
Sharon Gannon