The diversion of technology diverted
Tor is a distributed network designed to facilitate anonymous communication. It was developed by the Navy of the United States for the U.S. government to communicate data securely over the Internet. The tool was then abandoned and made available to the public under open source license. While it was originally adopted to protect users' personal data against interference by governments, the Tor network is now a technology used by some governments to monitor users on the Internet.
First, the Internet is a distributed architecture, the path of the packets can not be determined a priori - whatever the protocol used. It is therefore impossible to ensure that a message sent over the Internet will not be intercepted - or worse changed - by someone else. . Then, any message sent over the Internet involves a transfer of packets across multiple servers that are aware of either the source or destination of these packets.
These addresses (source and destination) are stored on servers and can then be retrieved to identify the identity of persons who sent or received packets. Finally, given that the transfer of packets over the Internet can be done through Internet access providers, they have the ability to control, and why not to filter everything that happens on their networks.
So there is no guarantee that a message actually arrives at destination without first being censored.