Haven't we been through that? There are lots of senses of "natural." Dictionary.com gives around 30 meanings. So metaphysically and methodologically, black holes would count as natural since anything posited by science is automatically naturalized, at least in part. That sense of natural, though, can become trivial, which is why I attempted to explain it in sociological terms, in "Atheism and the Endlessness of Explanation."

Anyway, the sense of "natural" I seize on for dualism is the one that's opposed to "artificial." And however natural black holes may be, in that they're part of the universe, they're also obviously opposed to the natural order in some sense, making for a viable distinction. That distinction is marked by the concept of the event horizon because there's a powerful asymmetry there: what goes into the black hole doesn't return until, as you say, the end of time itself, trillions of years from now when black holes will burst.

The underlying issue here has to do with the utility of distinctions. The monist has a very high standard for the legitimacy of distinctions. Indeed, no distinction meets the standard so that, despite appearances, everything counts as united. I take a more pragmatic view, according to which distinctions are valid if they help us understand things. "Natural vs artificial" and "black hole vs ordinary spacetime" are meaningful, useful distinctions.

The revolt in question, then, isn't based on "ignorance," but on pragmatic (rather than mystical) understanding.