“Saudi Arabia and the U.S. have created ISIS, albeit the U.S. has done so by default.”
No, US has not created ISIS/Daesh. This youtube video is worth the time https://www.youtube.com/watch?v=4MbRvqr34UM
What has allowed ISIS to form and to flourish?
1. Encouraging and arming Syrian rebels with no direct control.
2. A power vacuum in Northern Iraq.
Who was primarily responsible for #1 and #2?