You know, so what? Every major phone company around the world has an interface for (any) law enforcement to access their phones usage records and billing systems. Why do you think you have to prove who you are to get a fixed phone or sim card?
This sort of access has been around for decades, facebook is just another one of these. How hard do you think is it for an agency to already match call data/internet data records with names and addresses and build a real "comprehensive database about people, their relationships, their names, their addresses" You dont have to be on facebook to be watched.