Yes. Also there are seperate policies and rules for citizens and non- citizens at the border.
>So all countries denying reporters, human rights workers or dissidents or protestors to enter their borders are doing it correct, because the rule of law is inside borders not outside.
This discussion pertains to entry into the US.
Most of the students will have been in the US before, they are continuing their degree and just went home for the summer. If the FBI or whoever has something on them they can apply for a warrant and have them arrested. But the government instead chose not to admit them at the border.
It goes the opposite way as well, if the student chooses not to leave the government has to find something of substance and convince a judge, just saying "I want you out" doesn't cover it. Nothing of this makes sense, and as far as national security goes, I find it hard to believe that students are permitted near classified data.