[InclinedPlane]

You can "firmly believe" in whatever you want. That's not science, that's belief. The evidence points towards the existence of dark matter very strongly, and the evidence has eliminated the possibility of dark matter being made up primarily of black holes. Which, incidentally, do exist and are not "black stars" (the gravitational wave detections of merging black holes are the strongest evidence yet of the existence of black holes and don't leave wiggle room for alternate theories).

If you don't form your beliefs based on where the evidence leads you then you are not following science, period.