//you don't need to believe in fairy tales to have a moral compass.//
No, you don't, but if you have been brought up to believe there is a super-being watching everything you do and any transgressions will be punished in an after-life you are going to think twice about committing crimes. The current belief that the police never catch anybody, coupled with the fact that there is no belief in a super-being, helps to decrease crime-deterrence.