The US is the only country with codified freedoms from the government. Every other country has rights given by the government to their citizens. The US may suck every now and then, but the US constitution is one of the best things in human history. It protects us from governments like the UK that don't think they have any limits to control their citizens.
The US Constitution also guarantees birthright citizenship, but that doesn't mean the government will actually respect that right. The US Constitution only holds as long as people are willing to defend it.
It certainly wasn’t intended for the currently used purpose and will very much come down to “and subject to the jurisdiction thereof,” which anyone short of the best legal scholars in our country aren’t qualified to speak to.