Privacy is a natural right.
“I don’t care about privacy because I have nothing to hide” is similar to saying “I don’t care about free speech because I have nothing to say”.
Privacy and Secrecy are different. Secrecy ensures that nobody knows the content that are secret (example: Merger plans of a company, before releasing it). Whereas, privacy ensures that certain contents are not made available to the public, even though the public might know certain aspects of the content (example: Social Security number of a person, his marital status, place of birth, number of children, etc).