So why not say black holes are the only real things in the universe as not composed of star stuff.

Perhaps intuitively we know this, and are very uncomfortable with questioning how real this universe is and label black holes to decrease this intuition and anxiety which may theaten our vanity and view of everything a lot.

Some comfort can be had though that the giant black holes in the center of galaxies create tremendous amounts of invisible energy horizontally as detected by an orbiting device we use to see this spectacular display.  Then fear and dread can be replaced by some awe and wonder.  Science really is neat!