Far out in deep space, a base that acts like a generation ship was established hundreds of thousands of years before. The residents gradually forgot what they are and where they came from. Now, representatives of humanity open it up and find that those inside have evolved into horrible shadows of humanity, guided by the imperatives of life inside the base, mediated by the robots. They reproduce young and are nearly completely animalistic. The representatives give up hope of redeeming them and decide to destroy the base.
It's a short story. I'm guessing it was written from 1990 to 2010.