They’re new royals. Their ancestors didn’t live in a castle.
Your comment sent me down a little rabbit hole. Heh. The cartoonist was born in Ohio (OH…!) but grew up in Michigan. She even attended the University of Michigan. So, I’m going to Occam’s Razor this and say that’s the “U of M” she is referring to.
They’re new royals. Their ancestors didn’t live in a castle.