...that Saudi Arabia is our friend and ally.
Who is also one of the progenitors of ISIS. Yeah they are really our friend./sarc
You misunderstand completely, totally.
It is true, there are very fundamentalist Saudis that were and are involved with radical causes. Usama bin Ladin was exterminated in Pakistan rather than Saudi Arabia because he was disowned by his respectable Saudi family that happens to control what is perhaps the leading engineering and construction firm in the kingdom.
Usama was a Jesus like larger than life religious person that gathered disciples and they left their established existence and attacked the world. As a matter of fact, they continue to attack even as they are losing hundreds of faithful per week.
These radicals are in fact Islamic Reformers. They see Islam as losing the purity of the past to watering down by contact with the modern world and put their lives on the line to insure reversion to a pure state. The Arab league of which Saudi Arabia and the other Gulf States find the radicals intolerable