The trouble here is that this is a minor, technical nitpick, which I can't really support. "Natural" as a layman's term doesn't just mean "thing from nature" but also means "thing undisturbed by human activity". People here clearly mean this latter thing when talking about "natural". Which is pretty confusing, I agree. Languages should have a word for this, as it is clearly needed.
Also, observe that many humans don't like natural selection either. There are efforts, for example, to conserve species that are going extinct, no matter how natural or man-made the cause.
Natural already means "things undisturbed by human activity", among a good lot of other things. As long as there's a clear need for such a word, it would do us good to have a separate word for that, like notmanmade or whatever, because that would make discussions clearer.
Also, observe that many humans don't like natural selection either. There are efforts, for example, to conserve species that are going extinct, no matter how natural or man-made the cause.