Most likely they just go to the head of the ISP (I bet there's only one) and say turn the internet off or else.
You assume threats need to be made.
One doesn't get to be the head of a business in a country like Iran without being a True Believer.
they don't need to say the or else part since they control the whole country including the ISP.
Yep, everything connecting to the Internet goes through the TIC.
https://en.wikipedia.org/wiki/Telecommunication_Infrastructu...