THE NEED versus THE WANT
When humanity was still in the hunter-gatherer phase, eating meat was a need to be met. However, now that we have significantly developed as a civilization, the eating of meat has become more of a want.
True, some of the nutrients we need are still best taken from animals (in the portions or amounts required), but the way that many societies consume meat is already placing a burden on natural resources. Again, the environment is at stake, along with the delicate balance of flora and fauna.
[As a doctor, I used to think eating meat in moderation was healthy. But looking at current literature, I realized meat wasn't a “health food” at all. While nutrient-dense, animal flesh comes with harmful hormones, bad cholesterol, and saturated fat, all of which eventually cancel out the alleged health benefits of meat consumption. -Ed.]