Every people say the same than you about their own state, but it's just lies.
It's something that all people do, but it's ugly to say clearly.
The facts I cited (easily verifiable) speak for themselves, and they debunk such assumptions in regards to Iran.
If you are Persian in Iran likely you will have higher income than if you are non-Persian.
The kind of racial and ethnic diversity we see in North America and western Europea does not exist in Iran.
The Iranian population is racially homogeneous, Iranians for the most part are physically indistinguishable from each other no matter their linguistic backgrounds. Names aren't specific to linguistic sub-communities either. Same goes for clothing, with a few exceptions (mostly in rural areas).
In other terms there's generally no way to tell whether an Iranian citizen is Persian, Azari or Kurdish etc. Accents may be the only tangible factor of distinction but then again, there are so many local accents including among Persians themselves, that unless someone has studied them in depth, they will not always be able to deduce their interlocutor's linguistic backgrounds from listening to them. Moreover, those born in urban centers like Tehran tend to speak Persian free of accent.
Even the birthplace doesn't necessarily inform about the linguistic background of an Iranian, because linguistic groups geographically overlap and intermingle.
Iranians do not ask their compatriots what their "ethnicity" is. When they meet someone new, they may ask that person what area of Iran they're from, but never what their so-called "ethnicity" is. It's just not a factor of import in Iranian society.
And so on, all the f states of this world works that way. Of course there are Persian people poor in Iran, and Jewish people poor in USA, and Han Chinese people poor in China, but in a less amount than any other ethnicity in those countries.
As long as no concrete evidence is shown to back this up, it can't be considered factual. What is more, the majority of Iranians do not originate from a single sub-national linguistic community but are of mixed linguistic backgrounds. Intermarriage is more than frequent, it's the norm. So any comparison or ranking of "ethnic" groups in Iran is skewed from the outset.
And when people make mayhem in streets they are asking for money, but they never say that clearly, beause it's ugly to say it, and instead they say excuses and talk about lack of freedom, when they are really complaining about lack of money.
That's possible but it doesn't relate to "ethnicity". Those with an ethnicist outlook have no problem displaying it, and they are marginal minorities amongst their kin.