Oh, and this is a valid question. But it has a very simple answer.
They simply didn't believe that people who had been born Americans, and who had been Americans their entire lives, had any significant "divided loyalties" worth messing with.
In fact, when they were discussing the qualifications for members of Congress, James Madison (you know, the Father of the Constitution) said that he wasn't in favor of making candidates for Congress be citizens for a long period of time, because it would give a "tincture of illiberality" to our Constitution.
Well, it's Congress who actually passes our laws. And there were some (doubtless you would have been in this camp) who argued that ALL of our Congressmen should be limited to natural-born-citizens only.
James Madison, the Father of our Constitution, argued against that. And he, and others who took his views, prevailed.
Benjamin Franklin "did not completely oppose citizenship for a number of years, but, like Madison, 'should be very sorry to see any thing like illiberality inserted in the Constitution.'"
Madison was even against putting ANY citizenship requirement for Congressmen in the Constitution. He wasn't opposed to having a requirement, but he thought that Congress could take care of that, and that the Constitution wasn't the proper place to put such a requirement.
So you are really opposing James Madison, and Benjamin Franklin, and most of our other Framers. That's who you're opposing. Not me.
What does that make you? It doesn't make you a supporter of our Founders and our Framers. Because if you were, you wouldn't be arguing so hard against them.
Jeff, as you well know, the Framers set the bar for members of Congress lower than those for the office of President, which is the ONLY office which has the Natural Born Citizen requirement.
Your post is non-sequitur to the conversation.