"You can easily jam or overpower a faint satellite signal with a local ground-based antenna."

Not doable unless either you are in between the dish and the satellite, or have an extremely powerful transmitter with its directional antenna pointed to the dish, where all that power is needed to cope with the fact that the maximum sensitivity of the dish is towards the satellite, not your jammer. Which also means that they need one jammer and its antenna for every dish they want to silence. That would not scale well.