If you pretend God doesn’t exist, you can fulfill your wish to create your own rules.
Commonly, this has to do with rules about sexual behavior.
Freud’s ideology was founded on his premise that God doesn’t exist. From this flawed premise proceeded all his ideas about religion.
Don’t make the mistake of thinking Freud was some brilliant thinker who was able to derive a particular wisdom about God’s existence.
Here’s the Freudian thought process on the matter:
1) I want to make my own rules (the product of Sigmund’s id)
2) If I convince myself God doesn’t exist, I can convince myself God’s moral law doesn’t exist (this occurs in Sigmund’s superego)
3) If God’s moral law doesn’t exist, I can construct my own morality (here Sigmund’s ego receives the integration of his id and his superego)