Another argument against the "going dark" claim is that before smartphones and the internet, the only conversations the FBI could monitor was through phonelines and mail. These were known to be easily monitored and I doubt there was much more criminal activity happening through those then than now. I would argue that the conversations that have gone online are the interactions that were previously happening in-person…
This is perhaps one of the more simple and persuasive arguments against domestic surveillance and spying that I’ve heard.