You make a good point, although it is a bit redundant as it has been used by many vegetarians and non-vegetarians including myself. As a non-vegetarian, I think that man eating meat is in accordance with the natural order of things, just as an animal eating another animal is. With that said, as a society, we do consume more meat than we should. We are designed to eat primarily vegetables, with meats as a supplement. With all this in mind, I still have an interest in becoming a vegetarian.
How far could you take this? To include plants? Plants are living things to, but we need to sustain ourselves. It is a confusing question for me.