“Shouldn’t have been citizens anyway,” what does that mean?
The granting of citizenship to the children of people who were not in the country as citizens or legal residents is only a fairly recent interpretation of the 14th Amendment. Prior to that, the parents would have had to establish legal
permanent residency in order to confer automatic citizenship on their children based purely on being born on US soil.
This link will explain it better than I would:
http://www.claremont.org/publications/pubid.459/pub_detail.asp