This is an exceedingly simple point to understand and yet it is a mark of the general ignorance of our time that so many millions of people absolutely fail to wrap their minds around it. It really is not nice to fool Mother Nature. We destroy other species and their habitats at our own, very considerable peril. All of them. Anyone who doesn't understand this basic fact of life is seriously confused.
Nature deserves a high degree of protection.
A much higher degree of protection than the human race presently accords Her. The best way I can explain it is to say that on the whole I have found vegetarians to be more reflective and more attuned to the need to balance the human race's activities with the activities and natural rythms of the planet as a whole. Unfortunately, some of them may have to contract Mad Cow disease, or have quadruple by-pass heart surgery or something similar before they slowly begin to realize that gnawing on body parts chopped off the corpses of dead animals might not be such a good idea after all. I suspect that a vegetarian diet has a slow, subtle, yet profound effect on body chemistry over time, which cannot help but affect the brain, and hence, the thought process, as well. So you stop doing it.