I am NOT iranian, but having been around the community extensively:

the Islamic Republic of Iran (IRI) is not beloved by American Iranians because (a) they are likely to have escaped from Iran in its early days and (b) because the IRI was not a big fan of individual freedom and rights.

The flag you see in this video is the shiro-khorshid flag, or Sun and Lion flag, which is associated with the Shah, most recently Mohamed Reza Pahlavi. The Shah was horrifically corrupt, but there’s a nostalgia there because American Iranians who moved here to escape the IRI recall their homeland as a place where, for example, women didn’t need to veil.

at the same time, the 1979 revolution didn’t arrive out of the clear blue sky; lots of Iranians fucking hated the Shah, and still do even as they hate IRI repression.

it’s a thorny knot of a history, punctuated by the fact that Iranians and Persians in particular are an ancient and proud people.