Sorry, why can this not be a coincidence? I understand that the universe is smooth across large spaces similar to how a fog is smooth on larger spaces, and coarse on smaller ones.
But even then, given a large universe, why would this be mathematically impossible? If galaxies formed evenly everywhere, couldn't this have happened by coincidence? Which theory is violated here?
Sorry my knowledge is a limited "The great courses Cosmology" course from 2009