I know you lot all think in binary, but I'm surprised that the astronomical community does as well. Are they planets or stars? Why not have lots of categories? Spherical things range from very big down to quite small, and different size ranges have different properties.
Who says all brown dwarves form in the same way? There are at least three ways to make a black hole of a given size.
The universe may not be an either/or sort of place.
Take that, Occam!