There is a difference between arguing in favor of a natural right vs a civil right, and both are valid things to argue for in a society.

natural - I have an inherent, inalienable right to this civil - Regardless of if its natrual, I only want to live in a nation that has this other right protected. So I'll fight for it.

Your argument assumes that techno-libertarians are only arguing a 'natural right' toward anonymity.