People have a right to complete anonymity, and should be able to go across the majority of the Internet just as they can go across most of the country.
That’s what you are missing.
Don’t get me wrong, I am also in favour of a single government ID, but in terms of combatting identity fraud, accessing public resources like single-payer healthcare, and making it easier for a person to prove their identity to authorities or employers.
It should not be used as a pass card for fundamental rights that normally would have zero government involvement.