That is not true. That is a fiction that has come about since 1898 on the basis of a faulty understanding of the court's ruling in Wong Kim Ark. The history demonstrates that prior to the late 19th century, Slaves, Indians, British Loyalists after the war, Women married to foreigners, and the children of Foreign Diplomats have always been considered non-citizens even though they were born here. If birth here was the sole criteria, none of these people would have ever been excluded from citizenship.
Not even the English use the "born on the soil" standard for their Chief Executive. No, a King (or Queen) only has legitimacy if they are descended from a member of the Royal Family. The ONLY test for legitimacy in the English Executive is jus sanguinus. Being born in England is simply not good enough.
“If birth here was the sole criteria, none of these people would have ever been excluded from citizenship.”
You misread the post. I did not say, nor evern imply, birth was the sole criteria.
There is a material difference between children of diplomats, for example (who are not citizens, even now) and children of persons who have have consented to pay taxes and submit themsleves to the laws of the USA (such as resident aliens).
Children of legally resident aliens are natual born citizens.