This seems almost like a definition problem to me. In legal terms Murder means a very specific thing,namely to kill another with malice and forethought. That malice part is the bit that we're getting hung up on here. Malice is the deliberate desire to cause pain or harm. It seems to me that the goal when killing an animal for food is not causing pain. It is creating food.
If the question we are debating is "is it moral to eat animals", well that opens an entire different line of discussion.
The argument I find compelling is we don't stand in moral judgment over animals for killing other animals for sustenance, so why judge our own meat eating ways. All said and done, we humans are really just a rather clever animal. Our brains are well developed, but we are biologically mammals, just like myriad other animals. Why do we find to need to say that it is wrong for one type of animal to kill for food(namely us) but not wrong for another(lions).
In short we are alive so we eat. Biologically we have evolved as omnivores so we eat meat as well as vegetation. Calling our very nature into moral question is a path towards madness.
I think it's a better line of inquiry to wonder if our ways of raising animals have strayed off a moral path.
That all being said, I do salute those that abstain from eating meat for moral reasons. Few people have the strength to live by their moral convictions, and those that do are to be commended. Or at least admired for their drive.

pjkeeley wrote:It's natural for a man to want to rape a woman.

Wow. That's a fairly extreme claim. I am a man and I don't seem to be in a constant struggle with myself not to rape the females in my vicinity. Seems to me there is nothing natural about a desire to commit rape.

pjkeeley wrote:Lions can't decide not to kill other animals.

pjkeeley wrote:Animals rape each other all the time.

In the first quote above you state that Lions(and by extension, animals)are incapable of deciding not to do a thing(specifically kill another animal). Then in the next quote you say that animals commit rape. Rape is sex forced on another without their consent. Consent as an act is a form of decision. But you have already stated that animals cannot make decisions. This is obviously contradictory.

Scott wrote:Lions may eat each other, but lions aren't my role model.

I think we were talking about killing to eat. Lions are lazy and would rather hunt things that don't hunt back, like gazelles.
But, I'm willing to concede the point because I found your concluding statement very thought provoking.
Is giving up meat the next step in our process of bettering civilization? If so, why?
I have to run so I can't post my thoughts on this, but I will try to soon.