Yes they must deny the existence of God so that the state becomes the “creator” of our “unalienable rights”.
However, if the state can take our rights away then they were never “unalienable” to begin with. It’s all just a word game with them.
I don’t think they really believe in the concept of “unalienable rights”.
Because that would limit their ability to use their superior intellect and morality to impose cosmic justice on the society.