Could it be just because that galaxy has no central black hole? And if so that rises more questions: Does each galaxy have black hole associated with it? What

Could it be just because that galaxy has no central black hole? And if so that rises more questions: Does each galaxy have black hole associated with it? What if black hole is not a "point mass source" (a.k.a. singularity) but rather something with different curvature of space/time that we treat as a dark matter effect?