People have questions about immigration, and Google is giving this answer to some* users:
The reason it's "politically correct" to accept this Supreme Court decision is that it's good law. And the reason the Supreme Court said children born on American soil are US citizens regardless of their parents' immigration status is that this is what the Constitution says.
It's right here in Section 1 of the 14th Amendment (emphasis added):
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.
This is about as clear-cut as textual interpretation of the Constitution gets. There's nothing about visas or immigration status (no doubt in part because the country was operating on a largely open borders plan at the time) in here. If you're born in the United States, you are a citizen of the United States.
* Some Vox.com staff are seeing this result and some are not; some are seeing it only when logged in and not in incognito mode.