I don’t know why people are shocked
I see that people are shocked why the regime invites foreign Shias to their events or give them the permission to settle in Iran. Why are you shocked?
The ideology of the regime and their religion lost the soft war in Iran (especially the young generation and nowadays even many older people). The regime didn‘t manage that to make the generation of Nika Shakarami, Sarina Esmailzadeh, Majidreza Rahnard etc to like and identify with Islam even when they live a modern lifestyle. The average age of their supporters is very high you see very few young people among the crowd. Their generation is dying and they compensate the losses with Shias from foreign countries.
Islamist movements in other muslim countries at least manage to mobilize many young people but the IR really struggles to do that. New generation of Iran identifies more with the pre Islamic culture and history of Iran. They take pride in Cyrus and the Achamenids and don’t care about the 12 Imams or what happened in Karbala. That’s the reality and not a diaspora phenomenon. The IR knows that their ideology failed to attract Iranians so they start to indirectly reject the concept of an Iranian nation and start to make Iran a Shiite caliphate where every non Iranian Shiite is treated better than an average Iranian.