Except the Supreme Court has upheld various rights foreigners have w/r/t the bill of rights.
See in particular his quote from Scalia's dissent in Boumediene:
“The alien, to whom the United States has been traditionally hospitable, has been accorded a generous and ascending scale of rights as he increases his identity with our society . . . .
“But, in extending constitutional protections beyond the citizenry, the Court has been at pains to point out that it was the alien’s presence within its territorial jurisdiction that gave the Judiciary power to act.” Id., at 770–771.
Not even Glen Greenwald claims that the U.S. Constitution applies to non-citizens trying to board a plane in Cairo.
[1] Though many people would say it's a separation of powers violation.
Should the US treat visitors with respect and make the process of entering and leaving predictable and transparent? Yes. But saying foreigners have due process rights goes beyond should into must. And that is incompatible with our traditional views of sovereignty.