Surveillance is secret, and that's the problem - secret surveillance that gives law enforcement an advantage. As well as whoever in governmental and political power may choose to abuse this secret surveillance.
Throwing people in prisons or gunning them down is visible and able to be protested against - like is happening now.
How can people protest against something they don't know is even happening? It took Snowden to even know that.
Secrecy is fire, and humans ought not to play with it too much.