The development of religion is one of the distinguishing characteristics between a simple brutish existence and being civilized. One can not be both religious and uncivilized. Although I realize that is not what you meant, of course; you were merely being gratuitously insulting to religious people.
Truly I wish this held truth, but aren't there examples to the contrary enough? We have quite a few threads in this forum just about that, countless atrocities have been committed in the name of religion. I'm sure you know this, so could you elaborate your point of view?
I'm definitely not saying religious thoughts are worthless, my opinion is quite to the contrary, but one
can in my opinion definitely be both religious and uncivilised.
As to eating meat: humans have evolved on a varied, omnivorous diet. I have seen it postulated that the start of humanoid meat consumption made metabolic room for brain development, because it allowed the digestive system to become shorter and simpler. The same or an even richer (partly) carnivorous energy consumption, compared to herbivorous counterparts, allowed maintaining larger brains, the most intensive energy consumer of our bodies.
We have the teeth and digestive system that is neither completely herbivorous nor carnivorous, but a mix of both.
However, in modern times, the need for evolutionary advantage is definitely disputable, especially when it becomes increasingly unethical. At the very least, I feel I need to be aware that creatures need to die in order to sustain my meat consumption. That might sound rather trivial, but many people are appalled here if you actively confront them with it.
In the longer run, with exponentially rising world populations craving meat, production as it is now will not be sustainable. It is a heavily subsidised branch of economy already.
I guess at the moment I find meat to be too good to resist. Not the most ethical statement, but there you go.
In my opinion, humans are more valuable than animals though. Or better perhaps: humans are the most valuable animals. Progress, knowledge, exploration, culture; without humanity it would all be lost. Earth would be one of the billons of billions of planets drifting in an overly vast, nearly empty space.
To the thread starter: given the choice; kill a horse or kill your girlfriend/mother/sister. Would you really think about it for half a second?