Why did Saudi Arabia get a pass?
Because of petroleum and the need to eliminate Saddam Hussein.
Never forget that that governments in the ME are run like a crime family. They never trust one another because each is looking in how to bring down the others.
For outsiders to negotiate what they believe to be the status of an “ally”, really means to allow oneself to be used and abused. An “ally” especially is never trusted.
There was no “need” to get rid of Saddam.