Now SW says that there is a "natural" worldview and some "other" worldview, based on who knows what, which is the worldview that he holds.
Well, I would argue that every worldview is natural. Every worldview comes from the workings of someone's brain, and brains are natural. Brains are made up of biological and chemical reactions, as far as anyone can tell. So, until someone can demonstrate a non-biological, non-chemical brain process or function, we have to continue to assume that there are only natural worldviews. The difference is that some natural worldviews are based on concrete evidence, ie reality, and some are not.
And atheism is not by itself a worldview at all, only an observation about the world. Just look at the discussions we have about guns, education, health care, free will and so on to see that atheists don't all have the same worldview--we just don't think there are any gods.