I understand the constitution perfectly well, but it is obvious that you do not understand the Dred Scott decision. The clause you cite from the constitution pertained to runaway slaves. Dred Scott was not a runaway.
Taney's decision went far beyond the narrow question of weather or not Scott was entitled to his freedom as the Missouri court had decided. It went on to claim that no black person, slave or free, was a citizen, that even free blacks had no rights under the constitution, and in Taney's, words, no rights that any white person need respect, and that Congress, or even the states, did not have the power to restrict slavery.
Now you point out the clause in the Constitution, where Taney found a basis for any of that? He ignored the Constitution which had nothing to restrict the rights of any free person, black or white. He ignored both history, and the law. At the time of the revolution, and the framing of the Constitution, free blacks were voters in 4 of the 13 states, Washington's army at times consisted of up to 30% free blacks. On top of that, Taney voided the North West Ordinance which banned slavery in those territories. That law was passed by the Congress under The Articles, an then passed through the first Congress with a unanimous vote. That first Congress had a number of members who were also framers of the Constitution. And Taney claims their act was unconstitutional?
I just wanted to let you know I saw your message, and I consider it so far “out there” in terms of understanding that I just don’t see it as worth the trouble to reply.