When the 14th was written and ratified, there was no such thing as an illegal immigrant. The common law was that every non-slave baby born in the US, including its territories, was automatically a citizen.
The 14th extended that understanding to former slaves and babies of former slaves.
Under the jurisdiction clearly referred to those with diplomatic immunity. Do you really want to give diplomatic immunity to 12 million illegals. Think about the repercussions before you dig too big a hole for yourself.
“Do you really want to give diplomatic immunity to 12 million illegals.”
You win.