On a world-wide scale, meat-eaters are in the minority. Most of the world is vegetarian - not by choice, but because they are too poor to afford meat.
I was a vegetarian for about seven years, and a vegan for part of that time. I just wanted to drink all the beer I want, never exercise, and not get fat. It worked. I only quit when I started training mma. Today, I eat meat, but I will not go out of my way to do so. I hardly ever buy it at the grocery store, and I don't eat out a lot.
Supposedly, only meat contains B12, which is required by the body. But how come countless millions of Indian people don't have a B12 deficiency? There was a piece of research that answered that question, and the answer is.....bug turds. Insect excrement contains enough B12 to prevent the deficiency, and not all of it gets washed off.