> Religious fundamentalists tend to be less corrupt than whatever your baseline for politicians and rulers
Citation and some kind of proof needed here. It is very dubious proposition.
> because within their in-groups they're scoring each other based on those ideals
Their ideals dont tend to be "transparency, anti-corruption and fairness". Those three tend to be fairly low on the list of ideals they score each other on. For example, Iranian regime is considered very corrupt.
> they're not gonna behave like Saddam and just light money on fire for their own flamboyant luxury.
That is just a matter of aesthetics. Not a measure of coruption.