Indeed, Christie’s form of Republicanism emphatically needs to go away.
I cannot stand Christie Cream, but his stance I am sure was compelling to many republicans, as abhorrent as mutilation is. But, what is the counter argument vs government control? - I think it has to along the same lines as parents can’t decide their kids can smoke, drink alcohol, murder, etc.
Less government control is good, but medical ethics should come in to play. If I have a son who identifies as a pirate, should I be able to have a doctor amputate one of his hands and one of his legs, and removed one of his eyes? To me, the answer is clearly no. Should the government make a law banning these pirate transitioning procedures? No. Should doctors do these procedures? No. The “do-no-harm” oath should apply here and, IMO, medical ethics should dictate that these sorts of procedures should not be done until the person is old enough to give consent.