N380UA
Methinks you misread Whatsa. in that a) the First Amendment applies to all in the US - but not extraterritorially, so you're not covered by it before you enter the US and b) the DoJ is not making any restriction based on religion, but rather one based on a combination of nationality (not mentioned in the Bill of Rights) and profession.
The effect might be the same but the way it's implemented is important.