So...what?
Article I, Section 8, Clause 4 of the Constitution provides Congress with the power . . . To establish an uniform Rule of Naturalization . . .throughout the United States.1 The Supreme Court has described naturalization as the act of adopting a foreigner, and clothing him with the privileges of a native citizen.2 Pursuant to this authority, Congress may legislate terms and conditions by which a foreign-born national (alien) may become a U.S. citizen.3
It seems the Congress can determine who can get in and become a citizen.