I don't think that's true at all. Aliens are often convicted of crimes, incarcerated, and even executed if they commit a crime on US soil. Not trying to apply that to the Trump EO case, just speaking directly to your comment.
As far as the Trump EO case goes, I think the other poster is correct who says that if the law plainly says in black and white that Trump is correct and the court is wrong, he should be able to ignore them and proceed.
The Constitution gives judges the authority to decide controversies between U.S. citizens and non citizens, but if no U.S. citizens are involved there is no rule what they can do.