Yeah, in the eyes of a typical naturalist, everything is strictly governed by causes and effects, and all those things must categorically be natural. To preserve the semantics of this perspective is a struggle because most people see "natural" as the opposite of "synthetic", regardless of their attitudes about spirituality. As a replacement for "natural", I would suggest "non-synthetic". Everyone then can pretty much guess what you're talking about, and you no longer need the term "unnatural" as long as you stick with "synthetic".
The question posed by the OP arranges a language game - one that I believe is useless for everything but hindering conversation once you know to see things with a sense of "oneness".