I thought you were reading the footnotes. If so, you should have noticed their footnote 9, which reads
The Plaintiffs cite the natural born Citizen clause as Article II, Section 1, Clause 5 of the U.S. Constitution, but it is properly cited as Article II, Section 1, Clause 4. See also Ind. Code § 3-8-1-6.This is because the original Clause 3 was superseded by Amendment 12, so it's not counted in the numbering anymore.
The rest of your argument depends on the assertion that "becomes at the time of his birth a citizen" is not the same thing as "is a natural born citizen." I know that's an article of faith for some people, but no court seems to agree with you. (I know, I know, that just means all the courts are wrong...)
The Indiana court recognized WKA was not found to be a “natural born Citizen.” They admitted it.