You are arguing against no one. The "almost" indicated an admission it was possible. No one was accusing people in the past of being stupid. My point was about the practicality of it. Or to rephrase the same idea, what percentage of human communication do you think was encrypted in the 18th century compared to today?

That's why it works as an analogy to mass surveillance. Surveillance was always possible, but now it is scaled up so a much higher percentage of our activity is surveilled. The commonality is that computers made these two things much easier to do. The purpose of my comment was to show that's not inherently good or bad by showing one example of when that's viewed as good and another when it's viewed as bad.