What forces all these students to go through the cruel process of donations? Why don't they just protest and break free from this trend when they are well educated? Why do they so simply let go of themselves?
This is a thematic question.
The characters in Never Let Me Go place a cultural premium on conformity––for example, Kathy repeatedly emphasizes how "typical" she is, and Ruth blatantly copies the gestures of older students at the Cottages. The organ donation system seems to run relatively smoothly because everyone is willing to accept docilely their fate as donors. Conformity is a common topic for dystopian science fiction novels like Never Let Me Go, but Ishiguro is unusual in that he does not suggest a better alternative to conformity. With the exception of Tommy's brief tantrum in the field, no character indulges in any act of rebellion, large or small. The novel's universe is one in which conformity is an immutable quality of human nature.
Ishiguro highlights many forms of willful ignorance, of social issues (like the organ donations) as well as personal issues (like sex and virginity). Often, his characters shy away from pressing for information when they sense they do not want to know the answers to their questions. He suggests that willful ignorance is the mechanism by which social injustices are perpetuated.
http://www.gradesaver.com/never-let-me-go/study-guide/themes
