This is the 1800s classical, pre-relativistic idea of a "black hole". But it is mostly a coincidence that if you plug an escape velocity equal to the speed of l

This is the 1800s classical, pre-relativistic idea of a "black hole". But it is mostly a coincidence that if you plug an escape velocity equal to the speed of light to Newton's equations, you get a body with a mass and radius equal to the mass and event horizon radius of a black hole. But given the incredible predictive success of general relativity, there's little doubt that actual black holes are not just "dark stars" but fundamentally relativistic objects: regions of spacetime so warped that time becomes spacelike and space becomes timelike. Note that Kerr most definitely does not disagree; the entire point of the Kerr metric is that it's a solution (set of solutions) to the Einstein field equations.