States have no rights, only powers. They don't get those powers, for the most part, from the Federal government, nor from the Federal Constitution. They get them from the people of the state via the state Constitution. While I oppose the states having those particular powers, I don't see any power given to the federal government, any branch, to take them away if the people of the state give them to the state government, unless they violate the rights of citizens of the United States as protected by the bill of rights and the 14th amendment. Even then, only the "guarantee of republican government" clause (Art IV Sec 4 US Constitution) gives the federal government any power in the matter.
The point in this case is separation of powers, not "states rights".
You are correct, of course. I used the term "rights" haphazardly.