First, it is not a contemporary book; it is over 30 years old.
Second, and more importantly, rights are not a major issue in the book. It is not primarily about rights, but about other issues, such as social pressures, personal identity, group interaction, power, etc.

To the extent that The Chocolate War has anything to say about human rights, it would be about the way that people are seduced by power, the way that the desire to have power over one another destroys rights, and the way that groups and the desire to belong is shown to be more powerful than abstract concerns like rights.