Hurmanetar
New
I don't dismiss a Christian/Muslum/Jew/Buddist's intellect or intellectual development a priori.
It would obviously not be wise to do so - for a variety of reasons - not the least of which is that a person may choose to continue to operate within their religion even after they reach the point in their development of seeing through the exoteric and grasping the esoteric.
And intellect or IQ is only a component. There's also a variety of personality factors such as openness and orientation to authority.
And then there's life in general which offers some randomness in the mix. People might not be pushed to explore outside their birth religion or question their authorities unless circumstances beyond their control drive them to do so.
So "development" in this sense is not merely about intelligence and contains some degree of luck.
But the notion that there is a division between the exoteric and esoteric is common and is in fact baked into Judaism and Christianity. There were the outer courts and the Holy of Holies. And Jesus also spoke to the crowds in parables, but only gave the explanation to his few disciples. (Matthew 13)