Whereever people are starting from the assumption that there is only the natural that is philosophical naturalism.
And who does that?
My starting assumption is a need for evidence to consider that something exists. I apply that to natural phenomena and physical laws and - ping - ample evidence for me to assume they exist and to base my understanding of the world on that assumption.
I apply the same to gods and supernatural phenomena and - uh oh - no evidence whatsoever for their existence so I choose not to make my understanding of the world on a presumption of their existence.
But as I've said on many occasions - if you, or anyone else, comes up with compelling evidence for the existence of gods or supernatural phenomena then I will change my current view and incorporate an assumption of their existence into my understanding of the world. So far that has not happened.