Alright this is going to be quick and sloppy but that't how you carnivores like it right?
Starting at your biological composition, your teeth are not designed for killing prey, you have no canines or claws. Your jaws can grind horizontally unlike cats and dogs. Humans intestinal tracks are significantly longer with weaker stomach acids to digest fruits and vegetables, while meat eaters are shorter and strong because flesh putrefies with in the body and needs to be cycled thru as quickly as possible. If you take to the theory of evolution and that we evolved from primates than our original diet stemmed from leaves, fruits, and bugs. Occasionally some primates like chimps can be seen hunting other monkeys but its rare and constitutes the smallest percentage of their diet. With that said the meat that they ate was wild and clean. What were fed are animals that are being tortured their entire lives causing their genetic make up to be altered. Distressed cells appear different under a micro scope. They are pumped with antibiotics and fed feed that has been soaked in pesticides and drank tap water with its plethora of contaminates. These things on their own would probably never yield too hard of a negative result in your life but when they're stacked to together they become a formula for cancer, lethargy, brain fog, chronic fatigue, hormonal imbalance, and more. As for dairy human beings are the only creatures on the planet that drink breast milk for their entire life and its not even the milk of their own species! To step back and reflect upon that it's really quite an appalling act. Yet milk/cheese is nearly in every thing we eat. How could this be? A dairy farmer makes 7x as much money as a beef farmer. What kind of farmer would you like to be? Dairy right? So now we have to push the product and this is exactly what they did in the early 20th century. They worked with big marketing gurus at the time and lobbied the government to get in on the action. Now I bet you cant make it thru a normal day with out at least one dairy blatantly or covertly in everyone of your meals.
All source of energy comes from the sun, the plants collect that energy directly, herbivores collect it thru the plant, the next collects it thru the meat of that animal, and the next one after that. All the while the original sun energy gets diluted and contaminated with bad fats, cholesterol, parasites, and more. Skip the middle men and feed as close to the source as possible.
( I can go on for days )
If you are going to tout evolution as part of a reasoned argument for becoming vegan while ignoring the human ability to kill and butcher our prey with tools rather than rely on our teeth to do the dirty work, your conclusions will have an element of bias and would likely be considered invalid by any discerning reader. Meat is nutrient dense food for humans and once it is processed all we need do is grind it up a little more with our teeth and in this way, our lower-acid digestive tracts can make relatively short work of the meat. As you probably know given your discussion on the relative lengths of the digestive tracts, meat is much easier to digest than most plant material.
The rest of your argument appears to be more politically motivated and I would agree that this is probably a more compelling reason for one to venture into Veganism but you will run into the same issues you have mentioned as far as pesticides, contaminants, big marketing gurus and genetic modification (I know you said
altered) while pursuing this lifestyle as well. In order to avoid some of these pitfalls, you have to look specifically for organic foods which come at a premium price and are not necessarily pesticide free (unless explicitly stated) as many pesticides are still valid for use on organically certified crops and certified organic usually-but-not-always means GMO-free. Many people have been convinced that organic is "good" and therefore are willing to pay much more money for organic foods but don't you think this was marketed in the same way as the products from the dairy farmer you decry in your argument? There are scholarly articles that indicate there is no overall benefit to organically grown food and that they might be a detriment to humanity as the crop yields are lower and costs of production are higher than those of conventional farming.
Lastly, I would like to mention that energy can't be created or destroyed and I'm pretty sure it can't be diluted or contaminated with... stuff? Humans can't directly use the energy of the sun to power our bodies. Perhaps in the future it will be a reality but for now, we need to get the energy indirectly from our available surroundings as impure, unethical and unsavoury as that may be.