That's sort of an extension of the "if you've nothing to hide then you've nothing to fear" type argument. One can counter with "what if you're a journalist who

That's sort of an extension of the "if you've nothing to hide then you've nothing to fear" type argument. One can counter with "what if you're a journalist who published leaks of damaging government information and you're trying to protect a source" or various other scenarios where keeping your identity anonymous is legitimate and legal.