The 10th amendment doesn’t control federal marriage law and regulations in the military, for federal employment, in immigration, or in foreign policy, nor in appointment of federal judges and the Supreme Court.
(As a side note, I question if the federal entities of Clause 17 would be allowing gay marriage if the ill-conceived 16th and 17th Amendments hadn't been ratified.)
Getting back to state powers, since you mentioned federal marriage laws and federal immigration laws in your previous post, note that the Founding States made the 10th Amendment to clarify that the Constitution's silence about things like marriage and immigration means that such issues are automatically uniquely intrastate power issues.
And with one exception to federal laws based on powers which the states have never delegated to the feds, expressly via the Constitution, the Supreme Court has clarified that powers not delegated to the feds via the Constitution, marriage and immigration in this example, are prohibited to the feds.
”From the accepted doctrine that the United States is a government of delegated powers, it follows that those not expressly granted, or reasonably to be implied from such as are conferred, are reserved to the states, or to the people. To forestall any suggestion to the contrary, the Tenth Amendment was adopted. The same proposition, otherwise stated, is that powers not granted are prohibited [emphasis added].” —United States v. Butler, 1936.
The only exception to such federal laws is the power delegated by the states to Congress, evidenced by the "Full Faith and Credit" clause (Section 1 of Article IV), to decide the extent to which the states have to respect the official records of another state, the Defense of Marriage Act (DOMA) reasonable based on the Full Faith Clause.
But regardless that the corrupt media and activist justices want everybody to believe that the Supreme Court found DOMA unconstitutional, Section 2 of DOMA is evidenly still in effect and indicates that a given state doesn't have to recognized gay marriage performed in another state. This is why the Supreme Court ignoring the 10th Amendment-protect power of the states to make laws which prohibit gay marriage, and the lame response of the states to the Supreme Court's ignoring the issue reeks of a 10th Amendment-ignoring, pro-gay agenda scandal.
DOMA:
This Act may be cited as the “Defense of Marriage Act”.
No State, territory, or possession of the United States, or Indian tribe, shall be required to give effect to any public act, record, or judicial proceeding of any other State, territory, possession, or tribe respecting a relationship between persons of the same sex that is treated as a marriage under the laws of such other State, territory, possession, or tribe, or a right or claim arising from such relationship.
In determining the meaning of any Act of Congress, or of any ruling, regulation, or interpretation of the various administrative bureaus and agencies of the United States, the word 'marriage' means only a legal union between one man and one woman as husband anå∆d wife, and the word 'spouse' refers only to a person of the opposite sex who is a husband or a wife.
Ignoring the 10th Amendment and DOMA Section 2 with respect to state laws which prohibit constitutionally unprotected gay marriage is why the Supreme Court ignoring state laws prohibiting gay marriage, along with the lame response of the states to the Supreme Court's suspicious ignoring of the issue, reeks of a Constitution-ignoring, pro-gay agenda scandal.