“All religions share the golden rule.”
That would be fine IF there was religion that was based only on the golden rule. Even when a religion has the golfer rule, the rest of the religion may dissolve that ethical premise.
The best example is Jesus. Many Christians ascribe their religious identity to the sermon on the mount. They say they follow Jesus as a teacher, whether he was or was not a god.
That would be fine if it were not for the millions of people crucified, enriched, enslaved, impoverished, sanctified, burned as witches, and annointed as Popes in Jesus’ name .
Seems to me that there is a huge advantage to religions that worship monkey gods, burning bushes, or wisdom bearing ravens over those that tied “salvation” to the existence of a man-god.