In this post I am not trying to convince warmongers to become pacifists, nor meat-eaters to become vegetarians. I am suggesting that pacifism and vegetarianism require each other. If you're neither a pacifist nor a vegetarian, it's your business to read this or not.
A pacifist opposes violence, killing and war. And yet if a pacifist eats meat, he or she is accepting that some living creatures can be killed for our pleasure.
A moral vegetarian opposes the consumption of animals. And yet if a vegetarian supports war, he or she is suggesting that there are cases where killing, even of innocent people, is acceptable (for to support a war is to de facto support violence against innocent people).
I would suggest that a pacifist should be a vegetarian; while I understand a moral difference between humans and animals (though likely not as great a difference as you do), a pacifist should extend his or her opposition to killing toward non-humans, too. Animal suffering may not share moral equivalence to human suffering for you, but it is suffering, and you can abstain from moral culpability in such suffering.
And a vegetarian should be a pacifist: it is understandable not to want innocent animals to suffer and die for human benefit, but shouldn't you also oppose war, which requires some humans to suffer and die for other humans' benefit?
It is easier, at least in America, to call yourself a pacifist: at a practical level, most pacifists and non-pacifists don't behave terribly differently in their own lives. It takes a deeper commitment to be a vegetarian: you must sacrifice something personal, and you must live with your decision on a day-to-day basis (for what's more individually affecting or socially significant than how we eat our meals?). So the harder sell is to convince pacifists to become vegetarians: vegetarianism requires everyday work and responsibility that pacifism does not necessary require. It should be easy to convince vegetarians, opposed to unnecessary killing of animals, to oppose the unnecessary killing of humans.
Can pacifism and vegetarianism be mutually exclusive? For me, they can't anymore.