A number of Christian denominations still live in Iran today and include Assyrians, Armenians, Catholics, Protestants and Evangelical Christians. Although a minority religious group in Iran, Christians of Iran are free to practice their religion and perform their religious rituals. (see article)
Source: Payvand News of Iran
The other Iran 
Yes Christians are not free as they are in the US or in Europe and that is a pitty, but neither are muslim Iranians, which is not surprising in a dictatorship.
Still compare this to other Middle Eastern countries like Saudi Arabia, where there exists not a single church, although much more Christians work there than there are Christians in Iran.
The difference is intolerance in Iran just comes from the government but not from the public. This can be also observed when you compare the role of women in society with their role in neighbour countries.