I expect there were 10,000 who knew, and he’s the only one who spoke up. Now, the other 9,999 likely believed it was to thwart terrorism, as this was post 9/11. Maybe those who had visibility into who was being surveyed were checking to ensure the spying didn’t cross their ethical boundaries. Interesting to think of what each individual in the system was considering.
Oh, I think it's much simpler: the other 9,999 didn't care enough to risk continued employment. Security today was dearer to them than the hypothetical benefits to strangers.
(Perhaps worth noting: not to detract from what Mark did, but he was retired and therefore didn't have a job on the line. Credit to him for leveraging his position of privilege as a retiree to speak out about what he knew.)
