Rather than refuting my point, you've reinforced it!
This is what the Framers thought of ECL:
James Madison in a letter to Jefferson, Jan 18, 1800, states that admitting the common law as legal federal law of the United States "would confer on the judicial department a discretion little short of a legislative power" since federal courts would "decide what parts of the common law would, and what would not, be properly applicable to the circumstances of the United States" and thus would "erect them [judges] into legislators"
Thomas Jefferson in a letter to Edmund Randolph, August 18, 1799, wrote, "Of all the doctrines which have ever been broached by the federal government, the novel one, of the common law being in force and cognizable as an existing law in their courts, is to me the most formidable. All their other assumptions of un-given powers have been in the detail. The bank law, the treaty doctrine, the sedition act, alien act, the undertaking to change the State laws of evidence in the State courts by certain parts of the stamp act, &c. &c. have been solitary, unconsequential, timid things, in comparison with the audacious, barefaced and sweeping pretension to a system of law for the United States, without the adoption of their legislature, and so infinitively beyond their power to adopt."
You missed the point entirely. The court said the legal LANGUAGE in the Constitution had to be interpreted in light of English Common law, because that was the basis for the language of law at the time. The term ‘natural born subject’ had a well known meaning in common law. The Founders used it interchangeably with ‘natural born citizen’ - or at least the Mass legislature which approved the Constitution did. Thus the common law meaning of NBS tells us what the Founders had in mind when they used the term NBC.
If you want to know what the Founders had in mind when they used a legal term, you need to know what the legal term meant at the time they wrote it. That ought to be obvious!