To answer the second part of this question first: black holes do not suck everything in. Some objects can actually orbit black holes just like the earth orbits the sun: safely. This is possible because black holes have their own gravity just like our sun does, or like stars do in general. In fact, stars and black holes are quite similar, and more so than you might think.
The only real difference between stars and black holes is that black holes are small enough in terms of their radius, that that light cannot escape them. This is what gives black holes their signature appearance of black emptiness. A star, on the other hand is burning so much that it constantly emits light in all directions. But a black hole is the same as a star in that it can have objects in its own orbit.
To bring it closer to home, we have our very own black hole at the center of our galaxy. This black hole at the center of the milky way galaxy is gigantic. But even though this black hole is massive, we are not in any danger of ‘falling’ into it or being sucked into it. In fact, our solar system orbits around this giant black hole safely as a whole unit. The whole galaxy orbits around this black hole.
To answer the first part of the question: yes, a black hole will ‘suck’ things towards it and into it thanks to the gravity surrounding them. But this is only true for the objects in space that orbit to close to the black hole. Interestingly, this is not too dissimilar from a satellite that has been orbiting earth for years that falls to earth and crashes into the sea. Satellites in earth’s orbit are likely to fall to earth when they slow down due to friction with particles and dust in the orbit area of our planet.
Finally: the main answer to the question is simply that, although there are many black holes in the universe, there are not enough in close proximity of other astronomical bodies to suck them in. Black holes do have their own gravity but the likelihood of objects in space orbiting too close to them is very slim.