“The essayist claims that Iran’s govt is fascist. But they are rightwing and the boomercons on FR have assured me that fascism is leftwing.”
Yes, you ARE confused. First, forget about the left and right stuff. It can lead you down the rabbit hole.
Second, determine if Iran’s system is about powerful control by a centralized power, as evidenced by schools of thought such as Marxism, or if they prefer a system of government that recognizes pre-existing rights that are not to be infringed on by government.
That will give you your answer. BTW, Fascism, as practiced by WWII Italy & Germany and current day China is Marxism that permits some private ownership of business so long as it benefits the State.
(Sorry but I forgot to put that in my initial comment)