This article is wrong.

School prayer decisions were based on the Establishment Clause. Anyone can pray in school, but the school cannot sponsor that prayer.

Section 1. All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.

There are four parts of this. 1) Citizenship defined. 2) Priviliges and Immunities: citizens only. 3) Due Process clause: any person. 4) Equal protection: any person within its jurisdiction.

The article focuses mainly on equal protection. An illegal immigrant is in our jurisdiction; otherwise we couldn't arrest and deport them.