Earlier quoted context omitted.
The legislation I linked to suspends all constitutionally-guaranteed rights "at" the border (ie within 100 miles of a border crossing, including any airports with international flights) if you are not an American citizen. The suspension of constitutional rights has been tried and upheld by a number of SCOTUS cases. There is no international body regulating any other kind of right, despite the well-meaning intention o…
If you are not an American citizen you are still a citizen of some other country, which has its own obligations before its citizens to uphold their human rights, even when they cross someone other's border. This may end up ugly for the USA if they try to abuse that decision. Not every country in this world is Mexico.
So you want the country the person is traveling from to impose their Will on the country they are traveling to?