That feels like apples and oranges being compared. It's one thing to block out a specific country (we do this even now to some degree due to different visa rules for various countries) and an entirely different thing to block out a religion, especially one that has a respectable following already existing in your country. You would encourage outcries and riots while also being stuck trying to screen people for something you can't screen or check. For all they know, a person's following Zoroastrianism.
That feels like apples and oranges being compared. It's one thing to block out a specific country (we do this even now to some degree due to different visa rules for various countries) and an entirely different thing to block out a religion, especially one that has a respectable following already existing in your country. You would encourage outcries and riots while also being stuck trying to screen people for something you can't screen or check. For all they know, a person's following Zoroastrianism.