It's a very good question. I would say that the majority are being persecuted. There are more ayatollahs in prison today in Iran than there ever were under the secular government of the Shah. A special court was established in 1987 for the specific purpose of prosecuting dissident clergy. Ayatollah Montazeri, referred to by Ms. Tamas, who had issued a fatwa saying that the Bahá'ís had the rights of every other Iranian citizen, was supposed to be the successor to Ayatollah Khomeini. He's been under house arrest for the past 20 years.
So the Bahá'ís are the only minority that is categorically legally excluded. They're not recognized as a legitimate religious minority, so they have no rights under the constitution. But other minorities are under various degrees of pressure.
The point is that in an authoritarian theocracy, monopolization of religious truth is the basis of power. So one of the biggest threats to the regime are dissident Islamic clerics who say that for 500 years of Shia Islam, there has always been a separation of state and religion, and who believe that the orthodoxy of their faith requires a separation of political power from the spiritual life of people.