Even in U.S. v. Wong Kim Ark, the 1898 case most often cited by “birthright” supporters due to its overbroad language, the Court only held that a child born of lawful, permanent residents was a U.S. citizen. That is a far cry from saying that a child born of individuals who are here illegally must be considered a U.S. citizen.
Here is the concluding paragraph of the decision of the court in Ark v. United States:
The evident intention, and the necessary effect, of the submission of this case to the decision of the court upon the facts agreed by the parties, were to present for determination the single question, stated at the beginning of this opinion, namely, whether a child born in the United States, of parents of Chinese descent, who, at the time of his birth, are subjects of the emperor of China, but have a permanent domicile and residence in the United States, and are there carrying on business, and are not employed in any diplomatic or official capacity under the emperor of China, becomes at the time of his birth a citizen of the United States. For the reasons above stated, this court is of opinion that the question must be answered in the affirmative.
http://caselaw.findlaw.com/us-supreme-court/169/649.html
The court clearly state that although Ark was born of non-citizen parents who were citizens of China at the time of his birth, and owed allegiance to China, he was still a CITIZEN of the United States at birth.
If the author of this opinion piece actually read the court's decision, then he lied in order to prove his point.