Play that out a little bit and tell us how you get a functioning government [or collective society over 100K people] as a result.

"I didn't agree to that parking fine; I park where I damn well please."

"I didn't agree to not put rat poison on the food I sold."

"I didn't agree that John and Jane Doe owned that house."

"I didn't agree that we have a medical licensing board to determine qualifications for doctors/surgeons."

"I initially agreed to pay for that, but I now revoke my consent and don't wish to be bound by that earlier consent. I did not agree to recognize your courts as valid and able to enforce that civil agreement."

That's not a rebuttal against the argument. If you have a chicken and call it a bull, and I say "that's not a bull, those have horns, tails, etc", saying "well, try getting eggs from that" doesn't prove that chickens are actually bulls.

I'm claiming that a unanimous consent ideal is utterly unworkable at the scale that even a city government needs to work at, let alone state or federal government.

If the argument against a mostly functional existing government is that "not everyone consented unanimously and willingly", I think the claim that to require such makes things less functional is an in-bounds claim. You can argue that I'm wrong, but you will have a hard time convincing me that my claim was non-responsive.

Not all things need consent. You don't need the consent of someone violating other people's rights to punish them. You don't need the consent of 100% of the citizenry to make a decision on how to expend public funds. You do need someone's consent to take private income from them. Income taxation is wrong for that reason.