[dfc]

Its the entry nodes that the oppressive government would like to block access to. If you can build functioning circuits you can connect to "hidden services" that people have set up with tor. This is how the Silk Road operated.

How do you protect against the oppressive government blocking clients from connecting to the network?

In addition to the entry nodes published by the directory servers Tor nodes can be configured as bridges[1]. Bridges do not show up in the authoritative list of tor nodes. There is no public authoritative list of all the bridges so the oppressive government can not easily prevent clients from connecting to all of the bridges.

[1] https://www.torproject.org/docs/bridges.html.en