Since a hole is an absence or lacks metaphysical being, does this mean that black holes are absences?

Well it's where the gravitational pull is so strong nothing can escape, and sometimes when a star supernovas the remains collapse on themselves and create a black hole. So there used to be something there. But most of outer space is virtually nothigness. So, it depends on whether or not you want to see the gl half full or half empty so to speak.