"Black hole" is a coherent, testable idea. It has real world physical implications, and is the simplest explanation for what we do see. There isn't a Korean version of a black hole vs. a version accepted by the Kurds. There are no stories of black holes befriending humans. In fact, there is nothing about a black hole that seems to care about humanity.

"God" is a vague fantasy, invented by the first people and slightly updated as technology changed. It has been made concrete, yes, but in many different and irreconcilable ways since the dawn of human imagination. So you can't just "believe in God." You believe in some particular version of "God." And that version is probably dictated by whatever your parents believed, rather than by the actual state of reality.