The very first job listing I found refutes this: https://www.usajobs.gov/job/882256600
Open to "U.S. Citizens, Nationals, or those who owe allegiance to the U.S."
Open to "U.S. Citizens, Nationals, or those who owe allegiance to the U.S."
As far as I can tell, “those who owe allegiance to the US” doesn’t include anyone beyond citizens and nationals and is just there as boilerplate.