"Not in the section to which you're referring. In that paragraph about bearing arms, he's referring to citizens of a state.
Taney: "It would give to persons of the negro race, who were recognised as citizens in any one State of the Union, the right to enter every other State whenever they pleased ...""
Yes, he is indeed talking about "the people", or US citizens. US citizenship is what the word "It" refers to in the cut. It, referrs to being one of "the people", "It", would allow him to carry weapons in any State.
Note, that the case came before the SCOTUS, because a MO circuit court determined that Scott was a free man. The higher courts reversed and so did the SCOTUS. The MO compromise regarding slavery was tossed and it was affirmed that only the feds had the power to determine citizenship of the several States. It is impossible to be a citizen of a State and not a citizen of the US. It is only by virtue of US citizenship, that one can be a citizen of any State.
Taney:
"For, when they gave to the citizens of each State the privileges and immunities of citizens in the several States, they at the same time took from the several States the power of naturalization, and confined that power exclusively to the Federal Government. No State was willing to permit another State to determine who should or should not be admitted as one of its citizens, and entitled to demand equal rights and privileges with their own people, within their own territories."
Here's a larger cut that includes what US citizens could do, by virtue of being one of "the people". Since the States can not confer citizenship, it is only recognition that a person is one of "the people", that they can do as Taney illustrates:
"it cannot be believed that the large slaveholding States regarded them as included in the word citizens, or would have consented to a Constitution which might compel them to receive them in that character from another State. For if they were so received, and entitled to the privileges and immunities of citizens, it would exempt them from the operation of the special laws and from the police [p417] regulations which they considered to be necessary for their own safety. It would give to persons of the negro race, who were recognised as citizens in any one State of the Union, the right to enter every other State whenever they pleased, singly or in companies, without pass or passport, and without obstruction, to sojourn there as long as they pleased, to go where they pleased at every hour of the day or night without molestation, unless they committed some violation of law for which a white man would be punished; and it would give them the full liberty of speech in public and in private upon all subjects upon which its own citizens might speak; to hold public meetings upon political affairs, and to keep and carry arms wherever they went."
"In that paragraph, Taney is not referring to some United States citizen."
Yes he is.
Nope. "It" refers to the U.S. Constitution, Article IV, Section 2, Clause 1 which says, "The Citizens of each State shall be entitled to all Privileges and Immunities of Cirizens in the several states". If persons of the negro race were declared Citizens of any ONE state, then ...
"It" would exempt persons of the negro race from the operation of the special laws ...
"It" would give to persons of the negro race the right to enter every other State ...
"It" would give persons of the negro race the full liberty of speech in public ... and to keep and carry arms wherever they went.
The Dred Scott case pointed out that persons of the negro race were not citizens of anything -- not of the United States and certainly not of any individual state. The 14th amendment, ratified nine years after Dred Scott, made them (small "c") "citizens of the United States" and extended to them some basic privileges and immunities so they at least had some protections.