“Correct except that Persians are not Arabs”
They were not Persians. They were Arabs who were in charge in Persia after the Muslim conquest. This is true again after the Islamic Revolution in Iran: The Supreme Leader of Iran is expected to NOT be a Persian with only roots in Persian ancestry. He is expected to be a descendant of Muhammad, a “Sayyid” - hence the black turban as opposed to the blue or white. All of that means he would be an Arab in ancestry.
https://en.wikipedia.org/wiki/Sayyid#Sayyids_in_Iran
Aside from religious / sectarian differences, the persecution was also very much tied to differences in race/ethnicity, history, language, literature, culture, and ultimately, self-perception based on all the aforementioned.
The Iranians in the Arab world have been known as "Ajami" (derogatory) because of the different language they spoke / speak. And, how they revived it to be the national language once again, after 2 centuries of being forced to speak Arabic soon after they were conquered.
The same goes for the Kurds. The Kurds by majority are Sunni like most Arabs, but do Not identify themselves as Arabs; they know they are ethnically Iranic. A significantly contributing factor to their persecution even during Saddam's secular rule. As well as a reason the Turks, as a rule, don't like them.
"From what you describe it reminds me of those Mexicans who insist they are 100% Spanish."
I see what you mean; your comparison is interesting.
Though Mexico and Spain share the same language, mostly same racial background (not counting indigenous people in Mexico before the Spanish conquest), and are both predominantly Catholic.
The Mexicans who want to be perceived as Spanish are the ones typically in the USA, where 'Mexican' does not necessarily have positive connotations compared to being "Spanish".
Iran's "indigenous" population, however, has always been Iranian, with different ethnic (Iranian) groups - Persians being the largest ethnic group, followed by Azari (Iranian), as the second largest one.
The Iranian-Arabs (who live in Iran) are overall an ETHNIC minority. But they are also linguistically, religiously, and culturally, much more Iranian than 'Arab'. From what you describe it reminds me of those Mexicans who insist they are 100% Spanish.
"The Supreme Leader of Iran is expected to NOT be a Persian with only roots in Persian ancestry. He is expected to be a descendant of Muhammad, a Sayyid - hence the black turban as opposed to the blue or white."
Spot on!
Might add the current Supreme Leader is ethnically an Iranian-Azari. Not to criticize Azaris; just a fact --- btw, I've never seen a mullah wear a blue turban :-) - only black (Seyyed) and white (for not).