Originally Posted by
Endus
In addition to Belize's comment, all the US Code is secondary to the Constitution, and when any legislation conflicts with that Constitution, it cannot be enforced.
The President may have broad, sweeping powers under the section you listed, but he can not restrict immigration on Constitutionally-protected grounds, like religion. It doesn't matter what the US Code says, because the Constitution clearly states that the government cannot discriminate in that way, in anything. And the Constitution, not the President, is the highest law in the land.