Except that Starship is so huge that it “punches a hole” through the plasma, leaving an opening behind it through which signals can pass. SpaceX took advantage of that in this flight by installing Starlink antennas on the upper surface of the vehicle, allowing transmission of data up, away from the Earth, to the Starlink satellite constellation and back down from them to Earth. It looked like it worked for a while, but since the ship kept rotating I suspect the antennas were eventually burned away, or the plasma reached unshielded parts of it causing sudden destruction.
Starlink does a lot more things than advertised and that’s typical of Musk who thinks way ahead.
I’m amazed that the powers that be have let Musk do some of the things he has been doing.