And why is atheism needed to justify absolute state control of subjects? Religion has a long a brutal history of being used as a tool to enforce absolute control over people.
Atheism works better - there's no higher ideal that the state is supposed to be subordinate to. So the State can replace God entirely. More efficient than being merely a middleman.
What do you think Big Brother is?? All knowing, all seeing, all powerful, the arbiter of Truth... If that's not a replacement for God then we have different definitions.