Possibly the following reasons [1]:
OIL: There are American investors in Saudi Arabia’s oil industry. It might hurt the profits from Trump’s investments and his CEO friends in the oil industry.
REFUGEES: There doesn’t “seem” to be many refugees for Saudi Arabia although the 9-11 hijackers were primarily from Saudi Arabia.
The Washongton Post, “The seven nations targeted for new visitation restrictions by President Trump on Friday all have something in common: They are places he does not appear to have any business interests.”[2]
- The Truth Division, January 28, 2017 – Trump Didn’t Include Saudi Arabia In Immigration Ban… And Here’s Why
- The Washington Post, January 28, 2017, Rosalind S. Helderman – Countries where Trump does business are not hit by new travel restrictions