It’ encryption it seems that’s why they haven’t contacted us.
“So if you have an alien civilization trying to listen for other civilizations, or our civilization trying to listen for aliens, there’s only one small period in the development of their society where all of their communications will be sent via the most primitive and most unprotected means.”
This doesn’t qualify for dude, please. It qualifies for sublime. There is something in that statement which I can’t put my finger on.