Tina R. answered 11/13/19
PhD in Communication, Flexible, Creative, Native Persian/Farsi Tutor
This is an interesting question and it made me think. I would say, strictly based on my personal experience as someone born and raised in Tehran, Iran, I think Iranians do not normally use such insults towards people who are not their neighbors or somehow irrelevant to them historically. The reason might be that Iran is relatively homogeneous from a racial point of view compared to a society like the US. Some Iranians may use insulting words or phrases towards Arabs or Afghans (unfortunately so) or among themselves (one subculture making fun of another subculture within Iran), but generally speaking, their view on westerners is positive (with the exception of Great Britain which had a long history of political manipulation and exploitation of Iranian oil up until 1979 revolution). The view towards the US and Americans are generally favorable as well, simply because Iranians are a big fan of technology and education, and they perceive the US as a place offering better opportunities for life.
I hope this answer was helpful :)
Taa ba'd!
Tina