I am of the perspective that if you are accessing that book or newspaper or social media sites using company equipment and network resources, then the company, as the network operator, sets the terms and conditions of you using their network. That can extend to SSL decryption of all connections or blocking unwanted programs or websites or nothing at all, it is all down to the company policies at that point since they own the equipment and pay for the ISP connection.
I don’t think it’s a good idea to use company networking equipment or connections with the same expectation of privacy (or control) as an internet connection you pay for. (eg. Home ISP, wireless carrier, etc) Even consumer ISP connections have certain well-known protocols blocked at the carrier as part of the terms and conditions of utilizing the ISP’s connections. It may be your traffic, but it may not be your network it is traversing. Most network operators have an inherent interest in the traffic traversing their networks.