My 2c worth:
disagree with parts, agree with others.
Firstly, the area that the Brits and the French divided up after WW1 was the Levant, ie Syria, Lebanon, Palestine and Trans-Jordan. Also Iraq. These were all under the loose control of the crumbling Ottoman Empire. Iran was separate and already under the influence of the Brits as part of “the great game”. Iranians are insulted if you call them Arab. They are a different people, with a different language and culture.
I agree that the Brits and then USA behaved appallingly in relation to Iran after the Second World War. Won’t go into the history, but appalling. Corporate economic interests trumped a promising democracy.
Part of the promise of Ayatollah Khomeini returning to Iran and the deposing of the Shah in 1979, was the restoration of democracy. Instead they got a brutal theocracy with a weak elected parliament and a president with little power. It has been evolving into more a democracy, but it has been a case of 3 steps forward, 2 steps back. The last general election virtually wiped out every hardliner from every significant elected government position. (By the way, what defines a hardliner over there, depends on what issue is being discussed, so it is complicated.)
The following is what I have learnt, primarily from Talking to Iranians:
Despite the theocracy, and the various rules and restrictions, citizens, particularly in urban areas side step the rules. Unusually in that part of the world, they struggle to get younger people to attend mosques for Friday prayers etc.
It is simply untrue that they are natural enemies of USA. They are enemies because of 1979 in particular. Their theology is Shiite (only 10 to 15% of muslims are Shiite) and Iran is the leading Shiite country in the world. They tolerate Christians, Zoastrians and Sunnis in their midst (although Sunnis keep a low profile). Jews were virtually wiped out or left in the mid-20th Century. Members of the Baha’i faith are persecuted and are not allowed to attend university.
From what I have read in their media: They hate ISIS, Taliban and Al Qadea. No other religious group has suffered from ISIS as Shiites, because all hard line Sunnis regard Shiites as infidels. In Pakistan, for instance, on days of Shiite religious festivals they used to turn off the mobile phone networks to reduce the number of remote bombings, such is the hostility between the two branches of Islam.
During the height of the fight against ISIS, I read Iranian media which included conspiracy theories about ISIS being a creation of the CIA to kill Shiites, and allegations of secret flights from USA providing arms to ISIS to help them. This might all seem absurd to us, but it was in their media, and gives you an idea of how they see things.
in short, Iran is not a natural enemy of the West. It is the enemy due to unfortunate historical circumstances. History writers in the future will struggle to explain why USA was so keen to be friends with Saudi Arabia, where almost all the funding and theology for radical Islam has arisen from, and enemies against what should have been a natural ally.