Take away the naturalization act you take away the citizenship at birth. Of course then you need the naturalization act to vest citizenship at birth, but since since the act vested citizenship at birth there is no longer a need for a naturalization act, so you take away the naturalization act.... Round and round. Like snake eating its tail.
Take away the naturalization act and NO ONE is a citizen either natural born or naturalized. It is a decision fork not a loop. It is the naturalization act that defines the RULES OF NATURALIZATION (per US Constitution Article 1 Section 8).
The naturalization act says people who meet cases A - G are citizens at birth and do not require the naturalization process to be citizens, [end of decision branch].
Those that do not meet cases A - G are not citizens at birth and therefor, must be naturalized [jump to the criteria for becoming naturalized]