"Duality

The fight between two equals Good and Evil"

That's what I said, I thought.

In contradistinction to your statement:
"Dualism is the belief in both good and evil."

Which is not quite the same thing. Catholicism agreed that there is good and evil but considered that good (or God) was ultimately stronger than evil (or the devil).

On your other point that the centralised organisation of religion was the main bone of contention I concur entirely.

Frank L.