Theatre and pageantry.
Remember when O'Niel tried to sell machine guns to Jaffar rebels?
"This is a TOY!" Puts down the staff weapon, picks up a machine gun "And this is how you kill someone."
(Carter shooting at the swinging log, remember?)
The religion of the Jedi, is how the state makes sure that they have humble servants rather than psychopaths intent on being loved proportionately to their power to destroy.
Imagine if God wasn't made up.
How would you regulate the priesthood to make sure they didn't use God to clean up in Vegas?