Because it was unnecessary since the definition had been well known in common law as the Court in Minor versus Happersett noted when it quoted the definition again as the Court in The Venus case of 1814 had quoted it:
"The natives, or natural-born citizens, are those born in the country, of parents who are citizens."
And that definition has never changed.
Gosh, Uncle Chip, that's just way too simple.
Why don't we do this, instead? Let's have the Democrats nominate a guy to run for POTUS who doesn't meet that basic specification. Then, let's have the Republicans overlook it during a two-year campaign, so the American voting public can vote for the guy, after the election officials in 50 states overlook it to certify him on their official ballots. Then let's have The Electoral College overlook it and vote him into office, so the Chief Justice of the SCOTUS can overlook it and swear him in. Twice.
Now we can have four years of preoccupation with the President's eligibility while he leads the country to hell in a handbasket! What jolly fun! Gee, I wonder if there is any concrete plan taking shape somewhere to hobble the Kenyan Kommie if the other party sweeps into Congressional power in 2010, as they assure us they are going to do.
But why worry about that? Instead, millions of us will go to Washington, DC, stand in front of the White House and scream "GOTCHA, YOU BASTARD," at the top of our lungs. Whereupon, the ineligible sitting President will pack whatever he can steal from the mansion, and slip out the back door, leaving a resignation note on the hall table. Yeah, that'll work.
There is no happy ending to this national disgrace. In the meantime, we have a country to run, and our party has no plan to do so, and no leader to make one, and carry it out.
Some birther's argue that "natural born citizen" and "native born citizen" are not the same, now you present evidence that indicate they are.
Some birthers claim that citizenship naturally follows that of the father, passed on in the sperm, if you will - do you offer the above quote as evidence that the baby inherits citizenship from both the egg and the sperm?
The quote does not say "both parents" nor does it say "parents, one of which is a citizen", it is simply plural as "citizens" and "natives" are plural. We might assume that because natives and citizens are a broad class of people, more than one set of parents gave life to them, and that among those pairs of parents were some of mixed citizenship.