“It takes a court decision to state that the 14th applied to the children of slaves, not aliens”
Just because slaves were the main issue does not mean it only applies to slaves. People have this confusion over original intent, thinking we ought only to understand the core motivation, no matter what the actual language says. In fact, if the 14th amendment framers had wished for only former slaves and their children to be citizens, and not anchor babies, it would have been exceedingly simple to use different language. But they didn’t, and the language they used applies to anchor babies as well.
Something also to consider (I don’t know the answer to this) is what were the requirements to become a citizen when the 14th Amendment was written?
Did they have anchor babies in the 1880’s?