He was (technically) an illegal, not a citizen. I was under the impression that the Constitution was for US Citizens.
Imagine that you have always believed that you are a US citizen. The knock comes at the door at 1am. The FBI has obtained a secret warrant from a secret court based on hearsay evidence that you are, in fact, an illegal from the Middle East conspiring to blow up apartment buildings.
You are now not entitled to a lawyer or due process. Your family is never informed as to your whereabouts. Courts refuse your families entreaties that the FBI be forced to identify who it has in custody and when, if ever, they will be charged.
Just how do you go about proving that you are a US citizen? Driver's licenses and birth certificates can be faked. If you are not allowed legal representation or communication with your family and friends, what do you do?
The protections of the US Constitution refer to "people". The rights which are enumerated and all of the other rights of man are "unalienable". You have them because you are born human. Rights are not an invention of man they are the recognition of the endowments of a Creator. For those of us who are agnostic, they can be thought of as a recognition of the order of nature.
The mother bear has claws and is not asked to justify their possession. Her survival and the survival of her cubs depends on her ability to defend herself. "Human rights" recognize that humans deserve the same ability to make their own way in the world without having their government deny them the basic abilities that every organism relies upon.