Probably because that wasn’t the question at hand in either case.
What an interesting dichotomy! You now say that neither the 14th amendment, nor Wong Kim Ark were addressing the issue of "natural born citizen" because that wasn't the question at hand. Wonderful! We are making progress.
Yes indeed it cannot be denied that both groups of people were well familiar with the term, but intentionally did not use it. I say intentionally because I do not believe they are so foolish as to omit it by accident. It was a conscious decision on their part to NOT use the term "natural born citizen." They used the term "citizen", which just as Article II itself demonstrates, means something different from "natural born citizen."
The lack of the use of the term "natural born citizen" is a glaring example of the "dog that did not bark."