The Fall of man happened in Chapter 3. Man had become corrupted and all of nature had fallen, too. Man developed an appetite for dead flesh and to kill for the meat. Before the Fall, man ate plant-based products, and there was no killing of animals. Even animals didn't kill each other to eat. They ate plant-based foods.
The rest of your post only shows that God allows man to eat meat because it's not intrinsically wrong (not a sin), but nor is it encouraged. Because the appetite for dead flesh happened after the fall of nature due to original sin, there are potential physical dangers that accompany the consumption of dead flesh. Also, less consumption of animal products means less inhumane conditions and suffering of animals. Knowing that chickens, pigs and cows suffer by being crammed into very small, confined places most of their lives up to harvesting doesn't appeal to me. It's easy for people to rationalize and compartmentalize unethical practices of suffering animals so their passions for are satisfied. This is the same people who live to eat. I only eat to live.
Many things were different before the Fall. We should not be making up rules for human behaviour based on pre-Fall conditions. I see you ignored my point that your same line of reasoning suggests that we all become nudists. (There really are Protestants who claim this.)
If you choose to not eat meat, that is permitted, but there is nothing in Catholic teaching to suggest that there is anything wrong with meat-eating. Your argument from the pre-Fallen state is flawed and irrelevant.
God, Himself, decreed that "
every thing that moveth and liveth shall be meat for you." That is going farther than saying it is not intrinsically sinful. This is making meat-eating the norm.
You may have a legitimate point about problematic treatment of food animals, although it is hard to say how much of what we hear about this is propaganda. Personally, I am concerned enough about this to avoid "factory farm" products. I spend the extra money to buy food from a local butcher who ensures that the meat he sells is ethically raised.
It looks like it is easy for you to judge people who eat meat and look down on them. If the spiritual effect of your vegetarianism is pride and feelings of superiority, it is a very dangerous practice for you. If you have a spiritual director you need to discuss this matter with him.