Privacy as a human right is, indeed, new. The concept and the desire for it is old. Doing things and not wanting to get caught is as old as walking forward. What, you think the idea of cheating a romantic partner is new? That every military in history and prehistory exchanged letters with one another, saying what they were doing? That every important and "important" person always exposed everything they did and thought to everyone?
Also, keep in mind there's a significant number of serious journalists that need privacy in order to do their job of exposing crimes. I can already see you replying "They wouldn't need to do that if everything was public". True, but that would also mean that tyrants and wannabe tyrants would have incredible ease in killing everyone they disliked.