Vegans and vegetarians seriously think it's unethical to kill animals for food? And killing [lants is a ok because vegans and vegetarians decided they are lesser beings. I am opposed to cruelty and senseless killing of any being whether plant animal insect or even bacteria. I hate when people kill spiders and Anta needlessly. But did not one ever teach them about the circle of life? They seriously need to watch lion king. Call it God's plan or evolution and selection but for better or worse we are omnivores. The truth of the matter is vegans don't get all the essential proteins in the right quantity unless they eat a lot of soy or something like that or take supplemens. They even have to supplement vitamin b12 because plants don't have bacteria that make them. And supplement fat soluble vitamins as well. There's nothing wrong with that but claiming moral high ground is wrong I think. The only valid point they have is helping the environment and frankly it's up in the air if that actually does help or not because it's not simple addition you have to account for a lot of factors and I have not read up on a lot studies that prove that it's better. If science shows that it is then at least they have something but otherwise this whole holier than thou attitude is throughly unwarranted and completely ridiculous
The circle of life? A call to nature? Lions also rape, should we aspire to that too? Most of us can now go down to the grocery store and get whatever plant foods we want from around the world. I think we can do better than we did when we were struggling to survive in prehistory, or what lions do today for that matter.
As others have said, eating animals means also killing more plants (since humans eat herbivorous animals) than just eating plants directly, so any pro-meat argument about plant welfare is self-defeating.
And your statements about biology are false. Plant foods contain all the amino acids a body needs. Animals can't create the amino acids in protein, only plants can do that. Plants take nitrogen and synthesize amino acids and combine them into proteins. Your statement is based on the false belief that we need to eat an idealized ratio of amino acids. We now know that's not true, the body breaks apart proteins and stores the amino acids separately, combining them when necessary into whatever ratio the body needs. In fact, there's growing evidence that always eating a "complete protein" is bad for the body, and that amino acid imbalances from one meal to the next may actually have a cleansing effect on the body. Any anti-vegan argument that contains "because protein" is self-defeating.
As for the environment, the United Nations (hardly a vegan mouthpiece) looked at all the information and concluded animal agriculture is devastating for the environment. Hell, the meat industry has started acknowledging it: arguments are now sometimes made that factory farms are better for the environment than small scale animal agriculture because factory farms consume less land, less water, and less feed. So if you eat meat your choice is the animal agriculture that's worse for the animals, or the animal agriculture that's worse for the environment. It's a game that you can only win by not playing.