He is saying at the fed level. Marriage, abortion, guns and many are all suppose to be off limits for the feds. They are not in the Constitution and should be handled by the States; we should not encourage the feds to do what is not part of their approved powers.
What are the feds doing about marriage that is not part of their approved powers? (Or abortion, for that matter?)
The Defense of Marriage Law is out of their powers and them trying to get gay marriage is also out of it. It is not one of the enumerated powers. His whole thing is that it is not a federal power granted by the Constitution.
As for abortion it also is not a federal issue it is not covered by the Constitution it was made up by the USSC.