Why are half the posts on here conflating secrecy with immorality? You're all fine with keeping your (lets assume completely 'moral') email, bank details, salary, intellectual property, etc, etc secret without the presumption being "because it must be immoral" right?
You appear to be confused. As usual, the devil is in the details.
No one cares if everyone knows they have an account at Bank of America, but they don't want their account number revealed.
No one cares if everybody knows they have a gmail account, but they don't want their password revealed.
But no one wants everyone to know they have an AshleyMadison account, even if their authentication details are kept secret.
Please don't be so obtuse as to claim you don't see the distinction.