I feel it. My only point was that "the Constitution applies and border police are acting illegally" and "the Constitution literally has no force in these situations" are both simultaneously true.

Honestly illegal border crossers are the only ones who maintain their constitutional rights, because once they've crossed it is impossible to prove it unless someone actually saw them do it. I've read border patrol officers comment that if a US citizen is found at the border there's basically not much they can do unless someone caught them crossing in the act.