Encryption enforces privacy. In a world with no privacy vulnerable people are easily abused by people in positions of authority. Also note that the legal system is not a perfect mapping to human morality - things that are are legal are not always moral and things that are moral are not always legal. Hence it is dangerous to have a world where right and wrong is determined only by an all-powerful legal system.

In my opinion it is important for society to maintain the privacy that humans have experienced for thousands of years. Remember that mass surveillance of every conversation that you have ever had is new thing. Before the internet society had much more privacy. Encryption is a way to ensure privacy in the internet era.