> UAE's major issue with Saudis is their quiet support for Islamism as well.
What is the meaning of "Islamism" here? GCC is something like 98-99% Muslim by native population. Also, Saudi Arabia is the home of the two most important masjids in the Islamic world.
ISIS and Iran are pan-Islamist, which is the strain of Islamism that the UAE and Saudi Arabia fear most. Pan-Islamists don't respect national boarders, democracy, nationalism or monarchies.