"Art 6 ... says the Constitution is the "Supreme Law of the Land"."
Not quite. Article VI says, in part,
"This Constitution, and the laws of the United States which shall be made in pursuance thereof; and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land; and the judges in every state shall be bound thereby, anything in the Constitution or laws of any State to the contrary notwithstanding."
IF there is a federal law that conflicts with a state law, the federal law prevails.
"did the States not have to vote on the Constitutional Amendmets in the BoR to get them added in the first place?"
Yes they did. But that's not the process of incorporation to which I'm referring.
Prior to the 14th amendment, a state could abolish freedom of speech, establish a tax-supported church, or do away with jury trials in state courts without violating the Bill of Rights. After the 14th amendment was passed, the Supreme Court "incorporated" some, not all, of the BOR into the 14th amendment under the due process clause.
"While such rights as freedom of speech were clearly "fundamental," according to Justice Cardozo and the Supreme Court majority, others were not. Thus, the Supreme Court established the principle of "partial incorporation": Only certain "fundamental rights," not the entire Bill of Rights, apply to the states through the due process clause of the 14th Amendment. [Palko v. Connecticut, 302 U.S. 319 (1937)]."
"By 1972, the Supreme Court had "incorporated" into the 14th Amendment all but five rights named in the Bill of Rights. Those rights still not deemed "fundamental" include the Second Amendment right to bear arms, the Third Amendment protection against quartering troops in private homes, the Fifth Amendment right of grand jury indictment, the Seventh Amendment right of trial by jury in civil cases, and the Eighth Amendment guarantee against excessive bail and fines. (The Ninth and Tenth amendments do not name specific personal rights.)"
That the BoR didn't apply to the States is a convenient legal fiction for those looking to get around the strictures contained therein.
The conventions of a number of the States having at the time of their adopting the Constitution, expressed a desire, in order to prevent misconstruction or abuse of its powers, that further declaratory and restrictive clauses should be added. Pre-amble to the Bill or Rights
So now you have no less than FOUR different spots in the US Constitution giving it primacy in the areas specifically mentioned. The State governments are clearly LESSER and bound by the same stricture as far as the ennumerated Rights are concerned.
The very argument you are making is the same one the gun grabbers are using to justify thier actions. You aren't a gun grabber are you Bobby?