Yes, I got your point. Mine was that many of the things we do (specially online) cannot be protected by trying to keep it "secret" in the way you previously described. Because they often involve a "Bob", even if it's one we sometimes don't even notice.
So it makes sense for someone to try and look for ways to at least get some level of protection from Alices in other ways than just "don't tell Bob" even if they might not be flawless (you gave some examples of such ways in that last response).