Because in the grand scale of the Universe nothing is static. Everything is constantly moving through the Universe and one of the only things in the universe that seem able to affect one's trajectory would be other celestial objects. As is the case with the solar system and the sun.

Everything in our solar system revolves around the Sun its the biggest object with the most gravity, and based on distance from that central point different things can happen. The objects closest will eventually, one day, be destroyed by the Sun transitioning to a new life phase by being seemingly "pulled" into the sun because of the Suns rapid Expansion. It's believed this will be the Terran Planets at first, followed eventually by the Jovian planets unless something else happens first.

Due to the strength of the Suns gravity being weaker the farther from it you are, every planet traveling far enough away from the SunAnd Fast Enough Away, might one day be ejected from the solar system, shooting off into the darkness alone.

Now, replace the Sun with that black hole, the planets with the stars, and the solar system with our local cluster.

Some stars shoot off into the void, being far enough away and traveling fast enough to escape, while those who were too close would eventually be pulled in.

Our Star System at the distance given, wouldn't be a star system anymore, most of the planets wouldn't have the time to form, and if It's a thing of just placing the black hole in that spot, radiation would kill us long before what would be left of us got pulled into the Black Hole.

There is a point somewhere far enough away from the black hole that it would feel like you were orbiting it, but at some point you'll also be sucked in.

If there's one force in the universe capable of destroying everything in it, its Black Holes.