I don't think it is, but these philosophers I'm studying certainly do.
One of them, Peter Singer, makes a sound case for why we shouldn't eat animals or even kill them. He claims that we should first break down what it means that all men are created equal. He asks us to question the validity of that statement — mentally-handicapped people are less capable at certain things than non-mentally-handicapped people; those who are paralyzed are less capable at things than those who aren't; men are better at math and science than women; men are faster than women, etc. (These statements are made not on particular cases, but on an average.)
Singer then asks us to consider animals — he claims an adult dog has a one-up on an infant human. So, even though we walk on two legs and some animals walk on four or have scales, doesn't mean we should participate in 'specieism.'
Singer then goes on to detail why we shouldn't eat meat. It comes down to a simple explanation — animals can suffer because they can feel pain and pleasure, thus, they're like humans. Humans are smart enough to know what's painful and pleasurable, and can avoid pain and strive for pleasure. Animals can do the same (if you have a dog, think about it.)
He argues that humans only eat meat because of the taste, which isn't a necessity to live. He says we're only trying to appeal to our palate when, in fact, we can get the same nutrients from vegetables, soy beans, etc. Furthermore, Singer also says we shouldn't kill or eat animals because of the conditions in which they are bred. If we want cheap meat, farmers need to cut costs on land, housing and the like. The more cows we can fit into a cramped space, the less expensive meat becomes.
And that's why we shouldn't kill or eat animals, according to Singer.
Interesting, but I love medium-rare moomoos too much. Sorry, Singer.