The statute is exceedingly clear. Subsection (a) first says: "An alien present in the United States who has not been admitted or who arrives in the United States (whether or not at a designated port of arrival and including an alien who is brought to the United States after having been interdicted in international or United States waters) shall be deemed for purposes of this chapter an applicant for admission."
Subsection (b)(2)(A) then says: "Subject to subparagraphs (B) and (C), in the case of an alien who is an applicant for admission, if the examining immigration officer determines that an alien seeking admission is not clearly and beyond a doubt entitled to be admitted, the alien shall be detained for a proceeding under section 1229a of this title."
That applies to those who step across the border as part of a border crossing or rescue. The court decision applies it to all aliens, which is the never before applied part of GP.
The whole point of subsection (a)(1) is to treat all aliens similarly to those who cross the border for purposes of the chapter. Subsection (a)(1) is titled "Aliens treated as applicants for admission."
Subsection (a)(1) then says that "[a]n alien present in the United States who has not been admitted or who arrives in the United States ... shall be deemed for purposes of this chapter an applicant for admission."
Who is covered by the phrase "an alien present in the United States who has not been admitted?" What else could that phrase possibly be referring to?
Subsection (b)(2)(A) then says: "Subject to subparagraphs (B) and (C), in the case of an alien who is an applicant for admission, if the examining immigration officer determines that an alien seeking admission is not clearly and beyond a doubt entitled to be admitted, the alien shall be detained for a proceeding under section 1229a of this title."