The Sunni Arabs and Persian Shias have a long rivalry, now punctuated over oil wealth.
Many of these Gulf States have Shia minorities which are oppressed, like the Houthi tribe
The Iranian people's revolution of 1979 continues to pose a threat to the Sunni Arab Gulf emirates and Saudi Arabia.
CIA, DIA, CENTCOM J2 all knew that Shia Iran would retaliate against the Sunni Gulf States that host US military bases and do everything they can to undermine one of the few non-monarchies in the Middle East-- which is also a petro-competitor.
Moreover, the Iranian theocracy exposes the hypocrisies of the Gulf States and Saudi Arabia.
I watched caravans of wealthy Saudis drive across the King Fahd Causeway into Bahrain to drink, gamble, and whore around on the weekend.
The pious Iranian leadership doesn't do that.
This causeway was recently struck by an Iranian drone.
Poor hypocritical Saudis can't booze it up safely in Bahrain now.
caspianpost.com