I eat meat because I am selfish and lazy.
Selfish in that it is the food I look forward to most due to flavor.
I also enjoy obtaining meat.
Lazy in that it is very easy to get all your amino acids eating meat and a few other things in a day.
With plant matter it is a lot more complicated. Protein is not all the same, and you need all the amino acids required to build new parts of your body in your system at once to build and repair well.
With a plant meal this requires a lot of research into the specific amino acids available from each type of plant, and to prepare several types of protein at a time. This takes more energy and time, and can also be expensive.
Vegetarians that do not do this tend to be less healthy than their meat eating counterparts, you cannot simply eat a single plant protein and compensate. Protein ≠ protein.
Eating some amino acids one day and some another day doesn't really cut it to be thriving, but meat makes it simple. Many animal proteins have all the amino acids needed in one place. So it can build tissue easily.
Your body can synthesize some to compensate when lacking some, but only to a certain extent and it can also deplete enzymes and other nutrients if it has to synthesize a lot and those need to be replaced or allowed to replenish as well. Things are more complicated with plant proteins and only a plant based diet.
Thriving and being an active muscular vegetarian is a lot more challenging than just adding meat to a meal and making simple less complicated meals.
Meat simple, me bite meat.
However I also think that people trying to not eat meat for ethical reasons are doing something noble and I will not belittle them.
In a nation that kills somewhere around 10 billion domestic animals for food a year, not counting fish, a little less death can be a good thing.
Art Eatman said:
Nomadic hunter-gatherers don't create erosion. They do not drive species to extinction; they cannot do that, since when a food population drops below that of readily supplying food, they must move on--and return after that food supply rebuilds. Middens show generational usage over centuries of time. The best part, per the archaeologists is that they only "worked" some four hours per day to remain fed. Certainly beats 8 to 5, seems like.
Yes that was fine when the population on earth was minimal. When the population of human beings was a small fraction of other large animals. The planet could sustain a small population of humans that didn't have to contribute to raising, feeding, or growing food.
Today there is more humans than large wild animals.
In 1350AD there was less than 400 million people in the entire world, thousands of years prior there was a fraction of that amount.
Today we live in a single nation of 300 million, a world of over 7 billion, with China and India each having over a billion.
It is no longer a planet of primarily wilderness and a small number of humans able to reap a bounty from an exceedingly plentiful resource.
When Europeans first came to the western hemisphere most of it was unexploited. Flora and fauna abounded. Today we have some areas set aside where flora does okay, but fauna is still limited. Migrating herds of healthy thriving animals? No we have highways and roads and fences everywhere, and a comparatively small number that manage to survive in spite of it.
We went from having the most numerous bird on the planet, the passenger pigeon, to wiping it out.
Why was it wiped out? For meat, most of it was harvested to be sold for food in Europe.
Hunting can no longer sustain much of the population, in a single nation that kills 10 billion domestic animals a year, our wildlife would be wiped out very quickly if people replaced any decent sized percentage of that domestic food source with a wild one through hunting.
It was shown that market hunting results in extinction and wiping out of species. So hunting for profit, primarily to sell as food, was prohibited, after most of our wildlife were wiped out.
Today the same thing is happening in the oceans, the last open market hunting allowed, aka commercial fishing. A planet covered primarily in oceans, making up about 71% of the earth, has lost most of its sea life in half a century. Most of it for human consumption, aka meat.
Modern nets first started to be widely created around the 1960s, when synthetic fibers allowed the creation of thin, robust, long lasting gillnets, that could be larger and more durable and less visible than any previous hemp based or similar natural fiber net.
Nets went from small fragile things on the high seas that were easily seen under water, to large durable invisible things.
In that short period of time the majority of the fish have been wiped out. (There is still a lot out there, but the majority were still wiped out, it is a fraction of what was out there.)
Clearly the planet and a wild ecosystem is unable to sustain human beings unless they plan and raise their own animals for food.
Instead it is a limited resource that can be enjoyed recreationally, with some hunting and fishing.