IMHO, if its planned, manufactured, or learned, I don't consider it "natural".
Perhaps I am a bit literal because I have worked with too many predators who hide behind excuses of human "nature"?
The human mind is far too unconsciously programmed and socialized (often over generations) for me personally or professionally to consider it "natural" but rather learned. Much of what I see people calling "natural" is only "normal" for them due to habituation.
Yes, but animals in the wild also manufacture what are sometimes quite complex structures, and they learn through experience as well. Is that natural or not? What I'm saying is that learning and habituation is itself a natural process.
If you're saying that we should avoid habituation (ala Zen, or something similar), then that's another thing, but something like that is also a learned and trained process, so how would it be more "natural" than the other?