Typically from this perspective a man of the right will formulate this specific belief as if the Supreme Court of the United States randomly came upon ideas of homosexuality and coupling and have decided to inject their societal ideals into the concepts.
The truth of the matter is that so-called "Conservatives" decided to use the state to establish their idealistic views of marriage, and so Republicans used the powers of the state to establish through law what exactly a marriage is. That is a historical truth. A practical truth is that government fiat is a flexible thing that reacts, not always instantaneously, to a perceived will of the people or societal trends. A logical truth is that if and when you attempt to create a solid establishment of concept by using the State and its power of law then you create a situation were the State is empowered to make decisions regarding the disposition of the concept. In other words the federal government is empowered to make decisions as to whether a marriage can only be one man and one woman or involve a coupling of a different configuration of humanity simply on the basis that we empowered the federal government to make the decision as to whether a marriage was only one man plus one woman.
If these self-styled Conservatives, who weren't Conservative at all, did not call upon the federal government to have that power then they could not have been able to use it in such a fashion. Nobody should have been surprised that the same State that established the Defense Of Marraige Act when it was popular to do so would abolish DOMA when it was popular to do so. If and when you give the State any sort of power over you in the hopes and belief that they will use it as you like never be surprised if later on when the partisan hold on power shifts that the State will use that exact sort of power in a way you do not like.
Frankly though the establishment of DOMA was unconstitutional and immoral and an expansion of government power by any reasonable measure and stomps on the Tenth Amendment in so many ways. But for a little while it was "Constitutional" in that SCOTUS did not strike it down for many years. On the other hand what kind of law can it be if the Executive Branch does not enforce it?
A lot of "Social Conservatives" will ignore principle if a new law makes them feel good. So there is a branch of Conservatism that is not Conservative as much as judicial review is not necessarily activism.
Typically those like Todd Courser use the word "activism", as in "Judicial activism" only to describe a judge's decisions that they don't like. Mr Courser and Ted Kennedy have a lot in common that way.