Egypt (Sadat?) knew that although the Shah was an authoritarian, he was better than what was coming with the Mullahs. IIRC, Egypt was the first Arab country to accept Israel's place in the world. Egypt along with Jordan are the only two nations in the region that are reasonable since the Israel/Arab wars of '67 and '72?
For What it’s Worth,
and
In my Humble opinion.
These observations are based primarily on what happened and just slightly less on what was said.
I believe that as WWII was winding down there were very serious and high level discussions between the US and Britain regarding what to do with the Islamist in the Middle East and North Africa.
The conclusions I believe they reached were that these Islamist are literally insane and have no place in the Western World.
I believe they embarked on a plan that would support Islamic dictators if those dictators would keep their populace under control and keep them isolated from the rest of the World.
It worked for many years but now the genie is out of the bottle.
I must confess, I shed some tears when Sadat was killed. He was a good man, who evolved over time.