Well, the very reason for conceiving of dark matter is because there is evidence of gravitational effects from mass we cannot observe. So dark matter by definit

Well, the very reason for conceiving of dark matter is because there is evidence of gravitational effects from mass we cannot observe. So dark matter by definition must at minimum interact gravitationally, and be hard to observe by other means (electromagnetically, maybe even intent to the nuclear forces). Black holes sans accretion disk clearly satisfy these criteria.