Living breathing, means it grows and changes. It's why we have amendments.

The case was about parents who DIDN'T have legal status, but that the United States was considered to have jurisdiction over, so their child was granted US Citizenship.

His father and mother were persons of Chinese descent, and subjects of the Emperor of China - Justice Gray

was permitted by the collector of customs to enter the United States upon the sole ground that he was a native-born citizen of the United States. After such return, he remained in the United States, claiming to be a citizen thereof, until 1894 - Justice Gray

Entering the country under false-pretenses, doesn't sound like a legal immigrant to me...and yet...SCOTUS didn't seem to focus on that.