I think that mixing in "natural" with ethics will always steer a person wrong. They are not the same things.
Doing things because of wanting to do things "naturally" is a fine thing to do. I sympathize, and my default is to go for "natural" over "unnatural" in my personal consumption. I rather eat non GM foods, or wild grains, or less hybridized fruit... rather than the less "natural" versions.
But that is different than ethics. That is a liking, or a desire, and very important, but it is not ethics.
I have no qualms, ethically, against GM foods. My qualms against GM foods are based on health, and about the fact that is unethical for gov'ts and corporations to control what I eat without labeling or consent or information. But on it's face, GM food is not unethical, but it can still be something I fight against for the myriad other reasons.
Mass killing of animals for pleasure or custom, as it done in all cases but the handful of self-defense cases, is plainly unethical regardless of whether the killing is natural or not. This is because humans do not need to kill animals to thrive. We just don't. Even if eating were animals "natural", the fact that we don't need to eat them to thrive, and because we have a choice, makes this an ethical decision outside of the realm of "natural".
"The worker has the right to leave his boss, but can she do it? And if she does quit him, is it in order to lead a free life; where she will have no master but herself? No, she leaves to sell herself to another employer. She's driven by the same hunger. Thus the worker's liberty is only a theoretical freedom, lacking any means of realization; an utter falsehood."