yeah... I know that the centre of the galaxy is a black hole... but the sun impiegate 250000000 years to made 1 rotation, so the gravity effects are minimal. also, the Earth has its own gravity, right? so the effects are less than on a space station
It because of distance from center of the galaxy. As you probably know, gravitational force lowers with distance squared (Newton gravitation law Fg=k*m_1 * m_2 /r^2, k-gravitational constant, m_1 m_2 - masses of two object between which force is calculated, r - distance between them). Also be aware that solar system has quite high velocity around center of galaxy, angular velocity might be low, but distance from a center is quite high.
To stick with your example, an orbital station orbiting black hole would have to have high angular velocity to reach stable orbit. But stable orbit also means that gravitational force would be neglected by centrifugal force. As such, person inside space station would be affected only by gravitational force from space station itself. You would need to maintain unstable orbit by thrusters (or other type of engine) in order to have non-zero gravity inside station.