There are a few reasons. One is that black holes seem to defy the laws of physics as we understand them. For example, black holes are thought to be incredibly dense objects, with a very strong gravitational pull. But they also have a very high temperature, and emit a lot of radiation. This contradicts our understanding of gravity, which says that objects with a strong gravitational pull should be cold.
Another reason is that black holes are thought to be surrounded by a " event horizon." This is a region of space from which nothing can escape, not even light. This goes against our understanding of the universe, which says that everything is made of particles that can move around freely.
Lastly, black holes are thought to be at the center of galaxies. But, according to the electric universe theory, galaxies are actually electrically powered systems. So, if black holes are at the center of galaxies, it would mean that they are powering them, which goes against our current understanding.
ML - The way the world works - analyzing how things work