In addition to jamming the radio signals directly, Starlink terminals use GPS, so jamming GPS can hurt connectivity. Iran has been jamming GPS in an effort to reduce the effectiveness of foreign military attacks, but maybe they've stepped it up a notch in the past week. People in Ukraine are probably so accustomed to GPS jamming that they've all gone to Advanced -> Debug Data -> "Use Starlink positioning exclusively".

Ukraine has one other advantage: The jamming tends to come from one direction. If you set up a barrier on that side of the antenna, the signal from the satellites is less likely to be drowned out. People in Iran have no idea where the jammers are in related to themselves. If they're in a city, they might be surrounded.

Starlink terminals also require a clear view of the sky and they broadcast on certain frequencies, so it's quite possible for governments to find the terminals and confiscate/destroy them. Still, it's a lot more difficult to shut down than a few fiber optic lines.