The clerics that run Iran do not have enough bullets, nor do they have enough prison cells, to kill or lock up all of the Christians now practicing their Christian Faiths in Iran.
Sunday School and church services happen on just about every street corner in Iran on every Sunday these days and the Clerics have no other choice but to just allow it.
It's because of the sheer masses of their population.
About the only thing the clerics can do is attack their own media, suppress their votes, and shame them from their Mosques!
Say, isn't that what Donald Trump is trying to do here in America? LOL!