I think it would be more accurate to say that people vastly underestimate how they actually value their own privacy.

Remember the Holocaust? Well, one thing that helped was an initially mostly harmless ethnic census conducted by Napoleon. Then the Nazi got hold of that data, and used it. Oops. Not that you or your descendants actually risk being put down in the gaz chamber because you turn on your TV, but there's a whole range of nasty stuff that can happen between nothing and summary execution.