Today, many people use techniology with the mistaken idea that everything is free to use and abuse, if its on the net they can use it for anything. While that certainly is the prevailing thought and behavior, they are sadly ignorant of the law.
We live in a capitalistic society where all manner of things are owned, and with ownership comes privilege. Ownership by the government does not include ownership by the people. If you don't believe that go to the nearest park, pitch a tent, plant a mailbox and tell me how long that lasts (as soon as you are released from custody).
Everything is owned by someone, nothing is owned by the collective people.
Public Domain is a desgination that means that the owner waived his copyright rights. It has nothing to do with being owned by a Government Agency or being on the Public Record.
The government TV channel is freely available to the public, but it is owned jointly by the city and its contractor and it is copyrighted with "all rights reserved". That means it is NOT in the public domain, it is an owned work which you may view for your own personal use.