As with the Second Amendment and the right of individuals to bear arms the authors of the 14th Amendment made their intentions clear in their writings. Automatic citizenship was never meant to include children of illegals. Let's see if this Supreme Court gets it.
What matters is not what the authors said elsewhere that they meant, but what they actually wrote in the Constitution. Though in the case of illegal immigrants a case could be made that if they were subject to the jurisdiction of the U.S., they'd have already been deported.