Who else?
My brother - can you not see the obvious? In the same way you were trying to explain to me the "obvious" just after Russia invaded Ukraine?
It's hard to make people like you - when you are pointing a gun to their head or dropping bombs on their homes.
It may be even harder to be loved, when you haven't been in the country since you were 17 years old, and then suddenly reappeared only after a hostile state hacked your national tv network and showed your face.
Reza Pahlavi cannot be viewed as anything but an Israeli collaborator. No self respecting conservative OR liberal Iranian could support the person, that Israel brought on the tip of a sword.
The Pahlavi dynasty are a bunch of lowborn Mazandarani usurpers (not even Persians). His grandfather was a nobody - an officer in the Persian Cossack Corps. Not a drop of noble blood, no tribal lineage, no historical claim, and not even any ties to the previous Qajar aristocracy. They're no Romanovs... to put it lightly.
The way his father ruled - showed the extent of their origins. They make the Al-Sauds look like paragons of nobility and civility.
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The only real opposition to the regime are the Mujahideen-e-Khalq. Sometimes they bring these guys to the White House (John Bolton - big fan). They are Marxist Islamists. In the 1980s, they supported Saddam in his war against Iran, and this eroded much of the support they had within the country. Then throughout the 90s and early 00s they carried out bombings and assassinations across Iran. That pretty much completely marginalized them within Iranian society, and now they have a semi cult like reputation.
Still, the MeK is much more popular than some kleptocrat's son that hasn't lived in Iran since he was 17 years old.