The Saud's are a large royal family. Each man has four wives, their son's have four wives, and they all have children, with their wives and without their wives. These people, the uncles, the brothers, the children are all competing for the "family money" and power within the family. To understand this ugly mess, think angry relatives at the reading of a will and the division of "Dad's company".
Do we want to topple the part of the family that backs us? What do you think we should do?
The Saudis financed/planned/encouraged the 911 atrocities. Nothing has happened -- except they financed more.
Get rid of all of them. Plant nukes in Mecca and Medina to be used as response to another attack. Take over or set up a regime in the eastern portion of the country (Dhahran - Jubail-to the Kuwaiti border) where all the oil is. Let the imams have the Holy Sites.