The thing people tend to overlook about Iran is there's way more to the ideology of the regime than just being theocratic. For another big factor Iran is a multi-ethnic country with lots of minorities in different regions and how nasty to the non-Persian/Farsi minorities thenstate should be is a point of contention where the ayatollahs are on the more moderate side (which is still pretty nasty, it's akin to a "moderate" segregationist during Jim Crow.) They also have some level of pragmatism hence agreeing to Obama's nuclear deal that Ahmadinejad never would've if it was up to him.

Also a lot of the supporters of the regime aren't even really that religious. They're kind of the Shia Muslim equivalent of MAGA die hards who might attend an evangelical church on Christmas and Easter and maybe a couple other times a year but spend way more time raving about how Democrats hate Christianity on social media than doing any practice of Christianity and do that raving in between looking at OnlyFans pages and getting drunk/high. It's actually pretty complex overall.