Is there a reason why Esperanto is a lot more popular in Iran, compared to some countries like Arab countries in the Middle East and North Africa?
Apparently it was promoted after the Iranian revolution in 1979:
Ayatollah Khomeini of Iran called on Muslims to learn Esperanto and praised its use as a medium for better understanding among peoples of different religious backgrounds. After he suggested that Esperanto replace English as an international lingua franca, it began to be used in the seminaries of Qom. An Esperanto translation of the Qur'an was published by the state shortly thereafter. In 1981, its usage became less popular when it became apparent that followers of the Bahá'í Faith were interested in it.