What does that have to do with the Islamic Republic's bragging of conquering/ending Persian civilization in the name of Islam? A group should not celebrate conquering/ending a civilization. Especially so called religious leaders.
Iran is not Arab and is not occupied by Israel.
In your second statement you seem to callout the behavior, yet you defend it in the first? Calling for the death of random societal/structural groups, be that entire countries/societies, ethnic group, etc, is unacceptable behavior. It is especially unacceptable when it is done by powerful political leaders. It is outright evil when it is done by religious leaders.