It brings my mind back to the Penn and Teller "Bullshit!" episode where they tackle this topic (as bullshit! of course). On there, they have the Greatest Man in the World. Period. A man who singlehandedly has saved millions of lives. What did he do? He travelled all over the world, studying agriculture in different regions, and came up with better ways to do it all- and none of it involved organic bullshit- pesticides, preservatives, modified crops- all of these tools allowed him to feed millions of people.
These "natural foods" folks don't realize that they have the luxury of natural foods. Arable land is a finite resource, and it's only because we're the most prosperous nation in the world that we've got the freedom to choose natural foods over processed ones. Without these processes millions at least, possibly billions would starve.
Man-made chemicals aren't the problem. Pollution either. The single greatest problem in the world today is human biomass. All of the industrialization we live with comes are a result of the increasing population pressure.
Look at it this way- each living human being is using about 60kg of organic biomatter (my rough estimate of all the fleshybits) at any given time. With six billion humans, that's 360 billion kilograms of organic biomatter. This doesn't include the biomatter that has to be consumed to keep it running either- that's just the meat on our bones. Each human needs about 2000 calories, which involves eating about 5kg of biomatter a day, most of which ends up being wasted (again, a rough estimate). 30 billion kilograms of food.
The more energy and nutrients we can chuck into each acre of arable land is a big deal. Corporations want to do this because it can help maximize their profit margins, but we should want companies to do this to drive food prices lower- because lower prices come from abundance. If we want everyone on Earth to have enough to eat, that's our best option.
Then there's the idea that somehow, nature is better than technology. This arises from some mysticism surrounding nature. The idea of "Mother Nature". "Old Bitch Nature" is probably a better name. Perhaps you haven't noticed, but Nature wants you dead. You have to do incredible amounts of maintenance to keep this body nature gave you running. The amount of energy and water you have to fill it with, the fact that it can only survive in a narrow range of temperatures- there are very few areas on Earth where the climate won't kill you due to exposure. We've only got no natural predators because of our opposable thumbs- but, if they're hungry enough, there are plenty of big things that can eat us. Subsisting in a hunter-gather lifestyle is incredibly chancy- many of the options for gathering don't offer the right balance of nutrition, and then there are all those poisonous foods out there. Winters become a bitch, because you can't preserve food through them without preservatives. Face it- Nature wants you dead.
